Vascular implant

ABSTRACT

A vascular implant configured for occluding a vasculature of a patient having a biocompatible polymeric structure formed of a plurality of filaments spaced to maintain surface porosity and an inner radiopaque coil positioned within the longitudinally extending opening of the polymeric structure and attached to the polymeric structure. The polymeric structure and radiopaque coil are attached forming a joint at the distal end.

This application claims priority from provisional application Ser. No.62/524,419, filed Jun. 23, 2017, and is a continuation in part ofapplication Ser. No. 15/887,903, filed Feb. 2, 2018, which claimspriority from provisional application Ser. No. 62/457,871, filed Feb.11, 2017, and is a continuation in part of application Ser. No.14/997,094, filed Jan. 15, 2016, now U.S. Pat. No. 9,962,146, whichclaims priority from provisional application 62/105,648, filed Jan. 20,2015. The entire contents of each of these applications are incorporatedherein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This application relates to medical devices, and more particularly, tovascular implants for occluding vasculature and methods of manufacturingthe vascular implants.

2. Background of Related Art

An aneurysm is a localized, blood filled balloon-like bulge that canoccur in the wall of any blood vessel, as well as within the heart.There are various treatments for aneurysms. One endovascular treatmentoption for aneurysms is complete reconstruction of the damaged vesselusing a vascular prosthesis or stent-graft. A stent-graft is animplantable tubular structure composed of two parts, a stent and agraft. The stent is a mesh-like structure made of metal or alloy whichfunctions as a scaffold to support the graft. The graft is typically asynthetic fabric that is impervious to blood flow and lines the stent.Stent-grafts are not a treatment option for intracranial aneurysms dueto the risk of cutting off blood flow to feeder vessels that may bevital for brain function. Stent-grafts can also be stiff, hard todeliver/retract, and can be highly thrombogenic within the parentvessel, all of which are undesirable features for intracranial aneurysmtreatment. As a result, endovascular treatment of intracranial aneurysmshas centered on packing or filling an aneurysm with material or devicesin order to achieve a high packing density to eliminate circulation ofblood, which leads to thrombus formation and aneurysm closure over time.

There have been a variety of materials and devices described for fillingthe sac of an intracranial aneurysm such as injectable fluids,microfibrillar collagen, polymeric foams and beads. Polymeric resinssuch as cyanoacrylate have also been used. Both are typically mixed witha radiopaque resin to aid in visualization. These materials pose asignificant risk due to the difficulty of controlling dispersion and inretrieving them, if improperly or excessively delivered.

Mechanical vaso-occlusive devices are another option for filling ananeurysm. One type of mechanical vaso-occlusive device for the placementin the sac of the aneurysm is a balloon. Balloons are carried to thevessel site at the end of a catheter and inflated with a suitable fluid,such as a polymerizable resin, and released from the catheter. The mainadvantage of the balloon is its ability to effectively fill the aneurysmsac. However, a balloon is difficult to retrieve, cannot be visualizedunless filled with contrast, has the possibility of rupture, and doesnot conform to varying aneurysm shapes.

Other types of mechanical vaso-occlusive devices are composed of metalsor alloys, and biocompatible fibers, for example. Generally, thematerials are formed into tubular structures such as helical coils. Oneof the earliest fibered coils was the Gianturco coil (Cook Medical).This coil was formed from a 5 cm length of 0.036″ guidewire (inner coreremoved) and featured four 2 inch strands of wool attached to one tip ofthe coil to promote thrombosis. This device was difficult to introduceinto tortuous vessel sites less than 3 mm in diameter. This is generallybecause the coil was stiff or bulky and had a high coefficient offriction.

Chee et al. (U.S. Pat. No. 5,226,911) introduced a more deliverablefibered coil with fibers that were directly attached to the length ofthe coil body. This coil was designed for more tortuous anatomy bydecreasing the amount of thrombogenic material being delivered with thecoil. Other examples of coils are U.S. Pat. No. 4,994,069 to Ritchart etal.; U.S. Pat. No. 5,354,295 and its parent, U.S. Pat. No. 5,122,136,both to Guglielmi et al.

Materials can also be formed into tubes/strings/braided sutures (see,e.g., U.S. Pat. No. 6,312,421 to Boock; U.S. patent application Ser. No.11/229,044 to Sepetka et al.; U.S. patent application Ser. No.13/887,777 to Rees; U.S. patent application Ser. Nos. 13/552,616 and10/593,023 both to Wu et al.), cables (see, e.g., U.S. Pat. No.6,306,153 to Kurz et al.), or braids. Metal coils can also be covered bywinding on thrombogenic fiber as described in U.S. patent applicationSer. No. 12/673,770 to Freudenthal and U.S. Pat. No. 6,280,457 toWallace et al.

Unlike other tubular structures, braided or polymer coils can be furtherdivided into non-expandable and self-expandable devices. These devicescan be made from materials such as textiles, polymers, metal orcomposites using known weaving, knitting, and braiding techniques andequipment. Included in the weave or the finished braid can be optionalmono or multifilament fiber manufactured to impart additional featuresor effects (e.g., radiopacity and thrombogenicity).

Non-expandable braids (see, e.g. U.S. Pat. No. 5,690,666 to Berensteinet al.; U.S. Pat. No. 5,423,849 to Engelson et al.; and U.S. Pat. No.5,964,797 to Ho) can act as the implant and be mainly metallic, polymer,or a combination of metal and polymer. In such designs, braids have someminimal space between the filaments (braid strands) resulting in opencell designs. In addition, tight, mostly metal braids employing suchdesigns result in stiff structures which are difficult to track viacatheter or risk injury to the vasculature. Also, metal braidedstructures may be rough to the touch if not covered or furtherprocessed.

These braids can be formed into secondary shapes, such as coils thathave little or no inherent secondary shape, they can be dimensioned toengage the walls of the aneurysm, or they can have other shapes (e.g.random, “flower”, or three dimensional). These structures can also havea fiber bundle(s) in, or protruding from, the interior core made ofnatural fibers or thermoplastics infused with drugs to help withclotting (see, e.g., U.S. Pat. No. 5,423,849 to Engelson et al.; andU.S. Pat. No. 5,645,558 to Horton). Coiled braids can also be suppliedwith bio-active or other surface coatings (see, e.g., U.S. Pat. No.6,299,627 to Eder et al.).

Non-expandable braids can also cover core or primary structures, such ascoils or other braids (see, e.g., U.S. Pat. No. 5,382,259 to Phelps etal.; U.S. Pat. No. 5,690,666 to Berenstein et al.; U.S. Pat. No.5,935,145 to Villar et al.; and U.S. Pat. No. 8,002,789 to Ramzipoor etal.). Much like the above braid structures, these covers have open celldesigns (e.g., inner coil structure is visible through the braid).

Regardless of configuration, it is difficult to achieve high packingdensities and rapid flow stagnation with these devices as they have opencell construction which allows at least some blood flow through thewall, may not compress adequately, and/or may have limited bend radii.If an aneurysm sac is not sufficiently packed to stop or slow bloodflow, any flow through the neck of the aneurysm may prevent stasis orcause coil compaction, leading to recanalization of the aneurysm.Conversely, tight packing of metal coils in large or giant aneurysms maycause increased mass effect (compression of nearby tissue and stretchingof aneurysm sac) on adjacent brain parenchyma and cranial nerves. Coilprolapse or migration into parent vessels is another possible issue withnon-expanding devices, especially in wide neck aneurysms.

Braids may also be self-expanding and can be shaped into various formssuch as a ball, a coil(s), and a combination braid-stent. Examples ofself-expanding devices are disclosed in the following: U.S. Pat. No.8,142,456 to Rosqueta et al.; U.S. Pat. No. 8,361,138 to Adams; U.S.patent application Ser. No. 13/727,029 to Aboytes et al.; U.S. patentapplication Ser. No. 14/289,567 to Wallace et al.; U.S. patentapplication Ser. No. 13/771,632 to Marchand et al.; and U.S. patentapplication Ser. No. 11/148,601 to Greenhalgh.

Self-expanding braids are expected to occupy all or substantially all ofthe volume of an aneurysm to obstruct flow and/or promoteendothelization at the neck. A major problem for these designs issizing. The implant has to be accurately sized so that upon expansion itoccupies enough volume to fill the entire aneurysm, dome to neck.Undersized devices lead to insufficient packing as described above,whereas oversizing risks rupturing the aneurysm or blockage of parentvessel.

Neck bridges are yet another approach to treating intracranialaneurysms. They can be broken down into two categories: those that actas support to keep the coil mass from migrating into a parent vessel(coil retainer) and those that span the neck to obstruct flow into theaneurysm. Neck bridges that support the coil mass tend to bepetal/flower shaped and span the neck of the aneurysm or placed betweenthe parent vessel and aneurysm sac. Examples of neck bridges forsupporting the coil mass are disclosed in the following: U.S. Pat. No.6,193,708 to Ken et al.; U.S. Pat. No. 5,935,148 to Villar et al.; U.S.Pat. No. 7,410,482 to Murphy et al.; U.S. Pat. No. 6,063,070 to Eder;U.S. patent application Ser. No. 10/990,163 to Teoh; and U.S. Pat. No.6,802,851 to Jones et al.

Neck bridges that obstruct flow through the aneurysm neck can bedeployed either internal or external to the aneurysm and may not requiredeployment of embolization coils. Examples of intra-aneurysmal neckbridges with deployment at the base of the aneurysm sac with componentsextending into the neck are disclosed in U.S. Pat. No. 6,454,780 toWallace; U.S. Pat. No. 7,083,632 to Avellanet et al.; U.S. Pat. No.8,292,914 to Morsi; and U.S. Pat. No. 8,545,530 to Eskridge et al.Examples of neck bridges deployed external to the aneurysm (in theparent vessel) are disclosed in U.S. Pat. No. 6,309,367 to Boock; U.S.Pat. No. 7,241,301 to Thramann et al.; and U.S. Pat. No. 7,232,461 toRamer; U.S. Pat. No. 7,572,288 to Cox; U.S. patent application Ser. No.11/366,082 to Hines; U.S. patent application Ser. No. 14/044,349 to Coxet al.; U.S. Pat. No. 8,715,312 to Burke; U.S. Pat. No. 8,425,548 toConnor; and U.S. Pat. No. 8,470,013 to Duggal et al. Neck bridges canalso have surface treatment to encourage neointima formation asdisclosed in U.S. Pat. No. 6,626,928 to Raymond et al. Regardless ofdesign, neck bridges pose several problems when treating intracranialaneurysms. The first major challenge is deployment of these devices,which requires the bridge to be maneuvered and often re-positioned overthe aneurysm neck to assure complete coverage. Secondly, ifrecanalization occurs, any subsequent retreatment of the aneurysm willbe hampered due to access being restricted by the neck bridge or one ofits components.

Stents and flow diverters are similar to neck bridges in function, butare intended for parent vessel reconstruction and therefore run distalto proximal of the aneurysm, covering the neck. Such devices aredeployed in the parent vessel and are intended to act as a physicalblood flow barrier to induce sac embolization, stabilize embolic coils,and prevent coil protrusion and/or migration. Flow diverters, due totheir relative low porosity (high coverage), can be used with or withoutcoils and have been found to promote thrombus formation by restrictingblood flow into the aneurysm sac. However, complications such asrecanalization, delayed stent thrombosis, delayed aneurysm rupture, andstent migration have also been observed. An example of a stent isdisclosed in U.S. Pat. No. 6,746,475 to Rivelli and a flow diverter isdisclosed in U.S. Pat. No. 8,398,701 to Berez et al.

While the above methods attempt to treat intracranial aneurysms withminimally invasive techniques, there remains a need for a highlycompliant and thrombogenic filler that blocks blood flow within the sacof the aneurysm without the drawbacks of current devices. For example,it would be advantageous to provide a device that achieves sufficientflexibility to enable advancement through the tortuous vasculature intothe cerebral vasculature and achieves high packing densities whilemaintaining a high concentration of thrombogenic material. It would alsobe advantageous to provide a device that causes rapid clotting of theblood. It would also be advantageous to provide a device that promotestissue ingrowth within a relatively short period of time. Further, itwould be advantageous to provide a device that is soft, compressible andabsorbent to retain blood. Achieving all these objectives withoutfavoring/emphasizing one at the expense of another presents a difficultchallenge. This is compounded by the desire to provide such device whichis simple in structure and simple to manufacture without sacrificingefficacy. Further compounding the challenge is the fact that since thedevice is designed for minimally invasive insertion, it needs to be easyto deliver and deploy at the intracranial site as well as manufacturablein a small enough size for use in cerebral vasculature. That is, all ofthe above needs to be achieved with a construction that effectivelypacks the aneurysm without damaging the sac or other tissue whilepromoting rapid clotting and healing of an intracranial aneurysm withreduction in mass effect. To date, no device effectively achieves allthese objectives, with current devices at best achieving one objectiveat the expense of the others.

Additionally, a balance needs to be achieved in the overall devicebetween the stiffness of the device to maintain its heat set shape andthe softness/flexibility of the device to avoid damage to thevasculature and to enhance aneurysm packing. Additionally, inmanufacture, in attaching the components of the device, a balance needsto be maintained between sufficient stiffness and flexibility.Additionally, at the joints where the components of the device areattached, the balance needs to be obtained between a sufficiently longlength of the joint to enable a secure connection between the componentsand a sufficiently short length so that it does not create unduestiffness. If the connection, i.e., joint, is of insufficient length, itwill be too weak and the components could separate during deliverythrough tortuous vasculature and/or in use/placement within theaneurysm. On the other hand, if the connection, i.e., joint, is too longand thereby too stiff, it could be hard to deliver and in some instancespossibly undeliverable through tight turns in tortuous vessels and couldalso increase the risk of rupturing the aneurysm. Additionally, if toostiff, it could adversely affect the curvature of the secondary shape ofthe device. Moreover, if the joint has a solid (non-porous) outersurface, it prevents tissue ingrowth. Therefore, the longer theattachment (connection), the less surface area of the implant availablefor tissue ingrowth. Stated another way, the advantages of a shorterjoint are that it reduces the stiffness of the device and maximizes thearea for tissue ingrowth. However, the joint must be long enough tomaintain attachment of the components/materials. To date, no deviceeffectively achieves such connection objectives along with the otherobjectives enumerated above, with current devices at best achieving oneobjective at the expense of the others.

SUMMARY OF INVENTION

The present invention overcomes the problems and deficiencies of theprior art as it provides an implant with an optimal balance of theforegoing objectives.

In accordance with one aspect of the present invention, a vascularimplant configured for occluding a vasculature of a patient is provided.The vascular implant includes a biocompatible polymeric textilestructure formed of a plurality of filaments spaced to enable blood flowthrough spaces between the filaments. The textile structure forms atubular body having a first longitudinally extending opening extendingfrom the first end to the second end. The textile structure is crimpedto increase a thrombogenic surface of the textile structure. An innerelement is composed of an open pitched metal coil and has a secondlongitudinally extending opening extending from the proximal end to thedistal end. The inner element is positioned within the longitudinallyextending opening of the textile structure and is attached to thetextile structure at the proximal end and distal end. At least a firstportion of the inner element engages an inner surface of the textilestructure.

In some embodiments, a second portion of the inner element may be out ofengagement with the inner surface of the textile structure, the secondportion positioned between the proximal end and the distal end of theinner element.

In some embodiments, the textile structure has a wall thickness, and thewall thickness does not expand when the textile structure moves from adelivery position within a delivery member to a placement positionoutside (exposed from) the delivery member. The textile structure ispreferably configured to trap blood to promote stasis.

In some embodiments, the implant has a secondary shape in a helicalconfiguration. In some embodiments, the implant has a more linearconfiguration when positioned in a delivery member for delivery.

In some embodiments, the filaments form a plurality of yarns, theplurality of yarns having spaces therebetween for blood inflow betweenthe yarns. In some embodiments, the textile structure has a series ofpeaks and valleys along a surface of a wall to increase flexibility, thepeaks and valleys formed by crimping of the textile structure.

In some embodiments, the textile structure is a closed cell braid. Insome embodiments, the braid remains closed cell when in a curved shape.

In some embodiments, a radiopaque element is positioned within theimplant. The radiopaque element can include a tube having a helicalsection intertwined with coils of the inner element.

In accordance with another aspect of the present invention, a vascularimplant configured for occluding a vasculature of a patient is provided,the vascular implant comprising a biocompatible polymeric structureformed of a plurality of filaments and having a proximal end and adistal end, the filaments spaced to maintain surface porosity and thepolymeric structure forming a tubular body having a first longitudinallyextending opening which in some embodiments extends from the proximalend to the distal end. An inner element composed of a radiopaque coilhaving a proximal end and a distal end is positioned within thelongitudinally extending opening of the polymeric structure. Thepolymeric structure and radiopaque coil are attached forming a joint atthe distal end along a length extending for at least 0.002 inches andnot exceeding a length of about 0.050 inches.

In some embodiments, two windings of the radiopaque coil extend distallyof the polymeric structure, and the joint is formed where the polymericstructure covers at least two coil windings, i.e., where the polymericstructure and two coil windings overlap. In some embodiments, the twowindings are distalmost windings of the radiopaque coil. In someembodiments, the joint extends to a distalmost end of the radiopaquecoil; in other embodiments, the two windings are spaced proximally of adistalmost end of the radiopaque coil.

In some embodiments, the joint of the polymeric structure and radiopaquecoil is formed by application of energy to bond the polymeric structureand radiopaque coil. In other embodiments, the joint of the polymericstructure and radiopaque coil is formed by an adhesive to bond thepolymeric structure and radiopaque coil.

In some embodiments, the polymeric structure and radiopaque coil areattached forming a joint along a length of about 0.004 inches to about0.020 inches.

The implant can include a metal tube attached to a proximal end of theradiopaque coil, wherein the polymeric structure and metal tube areattached to form a proximal joint along a length extending for at least0.002 inches and not exceeding a length of about 0.050 inches. In someembodiments, a distal end of the metal tube is screwed into a proximalend of the radiopaque coil. In some embodiments, the proximal joint ofthe polymeric structure and metal tube is formed by application ofenergy or by adhesive to bond the polymeric structure and metal tube. Inother embodiments, the proximal joint of the polymeric structure, metaltube and proximal end of the radiopaque coil is formed by application ofenergy or an adhesive to bond the polymeric structure, metal tube andradiopaque coil.

In some embodiments, the polymeric structure and radiopaque coil areattached so that the joint extends continuously along the length.

In accordance with another aspect of the present invention, a vascularimplant configured for occluding a vasculature of a patient is providedcomprising a biocompatible polymeric structure formed of a plurality offilaments and having a proximal end and a distal end, the filamentsspaced to maintain surface porosity and the polymeric structure forminga tubular body having a first longitudinally extending opening. An innerelement composed of a radiopaque coil having a proximal end and a distalend is positioned within the longitudinally extending opening of thepolymeric structure. The polymeric structure and radiopaque coil areattached to form a joint at the distal end along a length wherein thejoint covers at least two windings of the radiopaque coil.

In some embodiments, the joint of the polymeric structure and radiopaquecoil is formed by application of energy to bond the polymeric structureand radiopaque coil. In other embodiments, the joint of the polymericstructure and radiopaque coil is formed by an adhesive to bond thepolymeric structure and radiopaque coil.

In some embodiments, the at least two windings are distalmost coils ofthe radiopaque coil; in other embodiments, the at least two windings ofthe radiopaque coil are spaced from a distalmost end of the radiopaquecoil.

In accordance with another aspect of the present invention, a vascularimplant configured for occluding a vasculature of a patient is providedcomprising a biocompatible polymeric structure formed of a plurality offilaments and having a proximal end and a distal end, the filamentsspaced to maintain surface porosity and the polymeric structure forminga tubular body having a first longitudinally extending opening. An innerelement composed of a radiopaque coil having a proximal end and a distalend is positioned within the longitudinally extending opening of thepolymeric structure. The polymeric structure and radiopaque coil areattached at a plurality of discrete regions at a distal portion, whereina distance from a proximalmost discrete region to a distalmost discreteregion is between about 0.002 inches and about 0.050 inches.

In some embodiments, the polymeric structure and radiopaque coil areattached by application of energy to form a series of spaced apart bondsbetween the polymeric structure and radiopaque coil. In otherembodiments, the polymeric structure and radiopaque coil are attached byan adhesive to form a series of spaced apart bonds between the polymericstructure and radiopaque coil.

In accordance with another aspect of the present invention, a vascularimplant configured for occluding a vasculature of a patient is providedcomprising a biocompatible polymeric structure formed of a plurality offilaments and having a proximal end and a distal end, the filamentsspaced to maintain surface porosity and the polymeric structure forminga tubular body having a first longitudinally extending opening extendingfrom the proximal end to the distal end. An inner element composed of aradiopaque coil having a proximal end and a distal end is positionedwithin the longitudinally extending opening of the polymeric structure.An outer band is attached to the polymeric structure and radiopaque coilto form a mechanical joint, the band having a length of between about0.002 inches and about 0.050 inches.

In some embodiments, the band is attached by swaging. The band can insome embodiments be radiopaque.

In accordance with another aspect of the present invention, a vascularimplant configured for occluding a vasculature of a patient is providedcomprising first and second biocompatible polymeric structures and firstand second inner elements. The first biocompatible polymeric structureis formed of a plurality of filaments and has a first end and a secondend, the filaments spaced to maintain surface porosity and the firstpolymeric structure forming a tubular body having a first longitudinallyextending opening extending from the first end to the second end. Thefirst inner element has a proximal end and a distal end and a secondlongitudinally extending opening extending from the proximal end to thedistal end, the first inner element positioned within the firstlongitudinally extending opening of the first polymeric structure andattached to the first polymeric structure. The second biocompatiblepolymeric structure is formed of a plurality of filaments and has afirst end and a second end, the filaments spaced to maintain surfaceporosity, the second polymeric structure forming a tubular body having afirst longitudinally extending opening extending from the first end tothe second end. A second inner element having a proximal end and adistal end, the second inner element having a second longitudinallyextending opening extending from the proximal end to the distal end, thesecond inner element positioned within the first longitudinallyextending opening of the second polymeric structure and attached to thesecond polymeric structure. The first and second polymeric structuresare connected at a proximal end during delivery and placement within thevasculature.

In some embodiments, the first and second polymeric structures areconnected at the proximal end and/or the distal end to a radiopaqueelement such as a marker band or coil. The first and second polymericstructures are each configured to trap blood to promote stasis.

In some embodiments, the first and second polymeric structures each havea series of peaks and valleys along a surface of a wall to increaseflexibility. In some embodiments, the first and second polymericstructures are closed cell braided structures. In some embodiments, thefirst and second inner elements are open pitched metal coils.

In some embodiments, the first polymeric structure and first innerelement are attached at the proximal end and distal end, and the secondpolymeric structure and second inner element are attached at theproximal end and distal end.

In some embodiments, the first polymeric structure is crimped toincrease a thrombogenic surface area of the first polymeric structureand the second polymeric structure is crimped to increase a thrombogenicsurface area of the second polymeric structure.

The present invention also provides in some aspects methods for fillingand infusing an intra-aneurysmal micrograft with blood or another liquidand delivering it to an intracranial aneurysm.

These and other features of the invention will become more fullyapparent when the following detailed description is read in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view partial cut away of an intra-aneurysmal micrograftin accordance with one embodiment of the present invention;

FIG. 2A is a view of another embodiment of the intra-aneurysmalmicrograft of the present invention having a larger diameter and thinnerwall;

FIG. 2B is a side view similar to FIG. 2A except showing the micrograftstretched to highlight the peaks and valleys;

FIG. 2C is a side view of the micrograft of FIG. 2A in a bent placementposition;

FIG. 3A is a side view of another embodiment of the intra-aneurysmalmicrograft formed into a helical shape;

FIG. 3B is a side view of another embodiment of the intra-aneurysmalmicrograft having a flared end to be directed by blood flow;

FIG. 4A is a side view partial cut away of an intra-aneurysmalmicrograft in accordance with another embodiment of the presentinvention;

FIG. 4B is an enlarged view of a proximal end of the micrograft of FIG.4A;

FIG. 4C is side view of a proximal end of an alternate embodiment of themicrograft of the present invention;

FIG. 4D is a cross-sectional side view of the micrograft of FIG. 4Aplaced over a mandrel before crimping;

FIG. 4E is a cross-sectional side view of the micrograft of FIG. 4Aafter crimping;

FIG. 4F is a cross-sectional view of the micrograft of FIG. 4A showingthe entire micrograft;

FIG. 4G is a cross-sectional view similar to FIG. 4F showing analternate embodiment of the micrograft;

FIG. 4H is side view of the proximal portion of the micrograft of FIG.4A with an alternate tube;

FIG. 4I is a bottom perspective view of the micrograft of FIG. 4A withthe braid cut to illustrate the inner coil;

FIG. 4J is a front perspective view showing the inner coil within thebraid;

FIG. 4K is a perspective view of the micrograft of FIG. 4A formed in asecondary helical configuration;

FIG. 4L is a close up view of a transverse cross-section of thefilaments of FIG. 4A;

FIG. 4M is a close up view of the braid of FIG. 4A;

FIG. 4N is a side view similar to FIG. 4F showing an alternateembodiment of the micrograft with a longer fuse joint;

FIG. 4O is a side view similar to FIG. 4F showing an alternateembodiment of the micrograft with a fuse joint spaced from a distal endof the coil;

FIG. 4P is a side view similar to FIG. 4F showing an alternateembodiment of the micrograft with a non-continuous fuse joint;

FIG. 4Q is a side view similar to FIG. 4F showing an alternateembodiment of the micrograft with a fuse joint at the proximal tube andproximal windings of the inner coil;

FIG. 5A is a side view of an intra-aneurysmal micrograft delivery systemin accordance with an embodiment of the present invention;

FIG. 5B is a side view of the delivery wire and mounted micrograft ofFIG. 5A;

FIG. 5C is an enlarged partial cross-sectional view of theintra-aneurysmal micrograft of FIG. 5B showing the mating of themicrograft with the taper of the delivery wire;

FIG. 5D is a side view of the pusher catheter of FIG. 5A without thedelivery wire;

FIG. 5E is a side view of an alternate embodiment of the micrograftdelivery system of the present invention;

FIG. 5F is an enlarged cross-sectional view of a portion of the deliverysystem of FIG. 5E shown in the locked position;

FIG. 5G is view similar to FIG. 5F showing the delivery system in theunlocked position;

FIG. 5H is a view similar to FIG. 5G showing the delivery systemwithdrawn and the micrograft fully deployed;

FIG. 6 is a side view of a rapid exchange pusher catheter for micrograftdelivery in accordance with another embodiment of the present invention;

FIG. 7 is a side view of another embodiment of the intra-aneurysmalmicrograft delivery system of the present invention having a pusher wirewith locking arms;

FIG. 8 is a side view of another embodiment of the intra-aneurysmalmicrograft delivery system of the present invention using a stent orflow diverter to push the micrograft;

FIG. 9 is a side view of an intra-aneurysmal micrograft introducersystem in accordance with another embodiment of the present invention;

FIG. 10 is a side view illustrating the loading of an intra-aneurysmalmicrograft delivery system of FIG. 5A into a microcatheter;

FIGS. 11A, 11B, 11C, 11D, 11E and 11F illustrate delivery of anintra-aneurysmal micrograft into an intracranial aneurysm in accordancewith an embodiment of the present invention wherein:

FIG. 11A shows the delivery wire inserted into the aneurysm sac;

FIG. 11B shows initial advancement of the micrograft into theintracranial aneurysm after removal of the wire;

FIG. 11C is an enlarged cross-sectional view of the micrograft exitingfrom the catheter corresponding to the position of FIG. 11B;

FIG. 11D shows the micrograft fully deployed from the catheter andpositioned in the intracranial aneurysm;

FIG. 11E is an enlarged cross-sectional view of the deployedblood-filled micrograft corresponding to the position of FIG. 11D;

FIG. 11F shows multiple micrografts of FIG. 11E positioned in theintracranial aneurysm sac;

FIGS. 12A, 12B and 12C illustrate directed delivery by the delivery wireof an intra-aneurysmal micrograft into an aneurysm in accordance with anembodiment of the present invention;

FIG. 13 illustrates delivery of smaller length flow directedintra-aneurysmal micrografts into an intracranial aneurysm in accordancewith another embodiment of the present invention;

FIG. 14 illustrates delivery of the delivery wire carrying theintra-aneurysmal micrograft through cells of a stent or flow diverterinto an aneurysm in accordance with another delivery method of thepresent invention;

FIG. 15 illustrates delivery of an intra-aneurysmal micrograft into ananeurysm using a delivery wire with the arms of FIG. 7 ;

FIG. 16A is a photograph of an uncrimped tubular PET braid alongside acrimped braid of the present invention to show a wave-like profile as inFIG. 1A;

FIG. 16B is a photograph of a crimped micrograft braid alongside acrimped micrograft braid that has been heat set into a coiled shape inaccordance with an embodiment of the present invention;

FIG. 16C illustrates a micrograft tubular body of the present inventionpartially filled with a fluid to illustrate the capillary effect.

FIG. 17 is a photograph of one end portion of the micrograft of FIG. 1A;

FIGS. 18A and 18B are flowcharts summarizing alternate methods ofplacing and deploying a micrograft of the present invention;

FIG. 19 is a flowchart summarizing viscosity lock function in accordancewith an embodiment of the present invention;

FIG. 20A is a side view of an alternate embodiment of the deliverysystem of the present invention;

FIG. 20B is a side view of another alternate embodiment of the deliverysystem of the present invention;

FIG. 21A is a side view of another alternate embodiment of the deliverysystem of the present invention shown interlocking with a micrograft ofthe present invention;

FIG. 21B is a top view of the delivery system and micrograft of FIG.21A;

FIG. 22A is a side view of another alternate embodiment of the deliverysystem of the present invention shown interlocking with a micrograft ofthe present invention;

FIG. 22B is a cross-sectional view taken along line A-A of FIG. 22A;

FIG. 22C is a top view of the delivery system and micrograft of FIG.22A;

FIG. 23A is a side view of another alternate embodiment of the deliverysystem of the present invention;

FIG. 23B is a side view of the delivery system of FIG. 23A interlockingwith a micrograft of the present invention;

FIG. 24 is a side view of another embodiment of the delivery system ofthe present invention delivering a micrograft and a flow diverter;

FIGS. 25A, 25B, 26A, 26B, 27A, 27B, 28A and 28B show a comparison of thebraid before and after crimping (the inner coil removed for clarity)wherein FIGS. 25A and 26A are close up views of the braid prior tocrimping and FIGS. 25B and 26B are close up views of the braid aftercrimping, FIG. 27A is a transverse cross-sectional view of the braidprior to crimping and FIG. 27B is a transverse cross-sectional view ofthe braid after crimping, and FIG. 28A is a perspective view of thebraid before crimping and FIG. 28B is a perspective view of the braidafter crimping; and

FIG. 29 is a side view of an alternate embodiment of the presentinvention showing a double braid attached at the proximal end.

DETAILED DESCRIPTION

The following embodiments are described in sufficient detail to enablethose skilled in the art to practice the invention, and it is understoodthat structural changes may be made without departing from the scope ofthe present invention. Therefore, the following detailed description isnot to be taken in a limiting sense. Where possible, the same referencenumbers are used throughout the drawings to refer to the same or likecomponents or features.

FIG. 1 illustrates a partial cut away side view of an intra-aneurysmalmicrograft for insertion into an intracranial aneurysm in accordancewith one embodiment of the present invention. The micrograft of thisembodiment, designated generally by reference number 10, includes abiocompatible non-self-expandable absorbent braided polymeric textiletubular body 12 that has been crimped to reduce stiffness and increasewall thickness and fabric density. The micrograft 10 has sufficientstiffness as well as sufficient flexibility to provide the advantagesdescribed below. It further is structured to enable a triple capillaryaction to promote blood clotting as also discussed in detail below. Themicrograft further preferably has a high surface area for increasedblood absorption, is radially deformable, has a low friction surface forease of delivery and can be shape set to enhance packing of theaneurysm. These features and their advantages are described in moredetail below. Note the micrografts of the present invention areespecially designed to induce blood stagnation or clot to rapidly treatthe aneurysm. The micrografts are configured for delivery to anintracranial aneurysm, although they can be utilized for occlusion inother aneurysms in other areas of the body as well as for occlusion inother vascular regions or in non-vascular regions.

An over the wire delivery system is provided to deliver the micrograftof the present invention to the aneurysm. Variations of these deliverysystems of the present invention are discussed in detail below.Preferably, multiple micrografts are delivered so that the aneurysm sacis densely packed.

Turning first to the biocompatible micrografts of the present invention(the delivery systems are subsequently discussed) the preferred tubularbody 12 of micrograft is constructed of substantially 100% 20 denier/18filament polyester (e.g., PET) multi-filament interlaced yarns, but canbe made of other combinations of denier and filament such as 10denier/16 filament yarn, or 15 denier/16 filament yarn, for example.That is, each yarn is composed of a plurality of polyester filamentshaving pores or spaces therebetween, and the plurality of yarns alsohave pores or spaces therebetween, for reasons described below. Thetubular body has a proximal end 14 and a distal end 16, with proximaldefined as closer to the user and distal defined as further from theuser such that the distal end is inserted first into the aneurysm. Bloodthen flows through the micrograft 10 in a distal to proximal direction.The tubular body 12 has a preferred inner diameter in the range of about0.001 inches to about 0.068 inches, and more narrowly in the range ofabout 0.006 inches and about 0.040 inches, for example about 0.008inches. It has a length ranging from about 2 mm up to about 150 cm and apreferred outer diameter in the range of about 0.002 inches to about0.069 inches, more narrowly in the range of about 0.010 inches to about0.041 inches, for example about 0.010 to about inches. Note thatalthough these ranges and dimensions are the preferred ranges anddimensions, other ranges and dimensions are also contemplated. Thesedimensions provide a sufficiently small size micrograft so that themicrograft can be navigated to and into the cranial vasculature forplacement within a cranial vessel.

Each of the multi-filament yarns are made of multiple wettablemicro-filaments, or fibers, assembled with spaces (pores) between them,referred to as inter-fiber spaces or pores. The pores are sufficientlysized to induce capillary action when contacted by a liquid, resultingin the spontaneous flow of the liquid along the porous yarn (i.e.,wicking). This capillarity between fibers (intra-fiber) within the yarnis termed as “micro-capillary” action. As a result, a sufficientlywettable and porous yarn will have high wickability and transport liquidalong its length. The multiple filaments also provide a high surfacearea and can be hydrophilic or hydrophobic.

This assembly of the two or more wickable multi-filament yarns into apermeable structure (such as a textile) results in a “macro-capillary”action, i.e., the transporting of liquid between the yarns andthroughout the structure. Such yarns and/or fibers can be textured,flat, twisted, wettable, non-wettable, with beads, of variouscross-sections (tri-lobal, multi-lobal, hollow-round, etc.), coated orhaving a modified surface, composite, reticulated, porous, pre-shrunk,crimped or modified using similar heat treatment or chemical processes.

The multi-filament yarns can be assembled into a textile tubularstructure using a braider or other textile manufacturing equipment andmethods. In general, the braider can be set-up with a program or recipe,spools of multi-filament yarn and an optional core mandrel to braidover. Anywhere from about 8 to about 288 strands of multi-filament yarnmay be used to form the tube, depending on the desired final structuralproperties such as density, picks per inch (PPI), porosity, compliance,etc. If desired, multiple braiders or a braider in combination with acoil winder can be run simultaneously to form a braid over braid orbraid over coil design.

The vascular graft (micrograft) has a proximal opening at the proximalend and a distal opening at the distal end for blood flow into thedistal end and through the lumen, (the proximal and distal openingsaligned with a longitudinal axis), thereby forming a conduit fortransport of blood through the continuous inside lumen (insidediameter). A capillary effect is created within the vascular graft whenthe biocompatible structure is exposed to blood such that blood istransported in a proximal direction through the distal opening in thevascular graft and through the vascular graft wherein blood clots. Thus,blood initially flows through the distal opening, through the vasculargraft and towards the proximal opening, with blood quickly stagnatingwithin the graft. In some instances, blood will exit the proximalopening (e.g., if there is sufficient pressure); in other instancescapillary action will only fill the graft and not cause flow out theproximal opening. The vascular graft retains blood, and becomessaturated with blood, to promote clotting. The outer member, i.e., thetextile structure, as disclosed herein is configured as a tubular memberfor flow therein, functioning as a capillary tube. That is, the tubulartextile member is configured in a closed cell fashion so as to form atube for flow therethrough, i.e., the lumen inside the textile structureis sufficiently small to enable function as a capillary tube, but thetextile structure still has sufficient sized openings/spaces forabsorbing blood through and along the yarns and filaments as describedherein. Thus, a continuous wall (continuous inner diameter) is formedalong the length of the textile structure to retain blood while alsomaintaining small spaces (micro-capillaries) in between fibers to wickand absorb blood. This closed cell or tight textile, e.g., braided,structure is maintained in the non-expanding embodiments disclosedherein since the diameter of the textile structure (and thus thediameter of the vascular graft) does not change from the delivery toimplant positions. That is, the textile structure is non-expanding suchthat when it is delivered to the aneurysm its outer diameter X is equalto its outer diameter X when positioned within the delivery member. Inan expanding textile structure, at least upon initial expansion orexpansion to a certain size/percentage, spaces between filaments and/oryarns would increase as the device expands to a larger outer diameter,thereby increasing openings so as to increase or create an open cellstructure. In some embodiments, the closed cell structure of theembodiments disclosed herein forms such small openings that the innerelement, i.e., the core element, covered by the textile structure is notvisible through the outer textile structure.

As noted above, the tubular textile structure (which forms a braid insome embodiments) forms a continuous circumferential wall along a lengthwithout large spaces between the filaments and/or yarns. This continuouswall is shown in the tight spacing of FIGS. 4A-4D and thus creates acontinuous outer member (low porosity wall) to contain and direct flow.In contrast, the use of large open pores between filaments would resultin an outer member (outer textile structure) with a non-continuous wallthat would allow blood to pass radially through the large pores or gapsbetween strands of the textile structure (forming a highly porous wall)so the structure will not contain or direct blood flow and thuscapillary action (effect) will not take place nor will it behave like avascular graft that transports blood therethrough. Instead, it will actmore like a net or strainer rather than a conduit for blood, let alone acapillary tube (tubular structure). That is, the yarns of the textilestructure in preferred embodiments are close enough to form a continuouswall to wick and transfer blood via the wall and inside lumen.

Capillary action, or capillarity, can be defined as the ability ofliquid to fill fine gaps or voids with wettable walls driven bycapillary forces that arise from wetting of the walls (e.g., fibersurface). Wettability, or wetting, is the ability of a solid surface toattract a liquid in contact with it such that it spreads over thesurface and wets it. Wickability, or wicking, is the spontaneous flow ofa liquid driven by capillary forces. Capillary flow through a textilemedium is due to a meniscus (wetting) formed in microscopic,inter-connected voids between fibers and yarns. Wicking in a textile orfibrous medium can only occur when a liquid wets fibers assembled withcapillary spaces between them. Because capillary forces are caused bywetting, a structure experiencing capillarity is constructed of wettablefibers with sufficiently small, inter-connected gaps. Since the textilestructures disclosed herein are composed of wettable yarns and the yarnsare made up of wettable fibers, which wick blood, capillary flow in sucha wall structure of the textile structure can be considered as thefilling of capillary spaces between fibers within a yarn (inter-fiber)and between yarns (inter-yarn) in the wall of the textile structure. Thecapillary spaces formed between yarns can be termed as macro-capillaryand capillary spaces formed between individual fibers of a yarn may betermed micro-capillary as described herein. It should be appreciated thecapillary action occurs as the yarns making up the wall of the textilestructure and the fibers making up the yarns are assembled close enough,as shown for example in FIGS. 4A and 4M, to create micro-capillariesthat induce wicking as in the textile structure of the vascular graftsdisclosed herein. Thus, the tubular textile structure of embodimentsdisclosed herein utilizes the three capillary actions (i.e., inside(inner) lumen, inter-yarn and inter-filament capillary actions) to actas a capillary tube and also achieves blood retention inside the tubularstructure. As can be appreciated, capillarity is dependent on pore size,meaning gaps in the textile structure have to be sufficiently small toinitiate capillary flow (i.e., smaller pores or spaces result in betterwicking). The textile structure will not induce capillary action ifthere is excessive porosity of the textile structure.

The vascular graft of the present invention advantageously promotesblood clotting, i.e., induces blood stagnation or clot to rapidly treatthe aneurysm. This is achieved in part by the construction of thevascular graft holding blood therein once blood permeates the graft. Theblood in some embodiments permeates the graft when still held by thedelivery member and positioned in the aneurysm.

By forming the textile structure as a tubular member (rather thanwinding/braiding the filaments about an inner element), and theninserting/positioning the inner core element therein for attachment tothe outer textile structure, portions of the inner surface of the innerwall of the textile structure are in contact with the inner element. Insome embodiments, these contact portions can be end portions. In otherembodiments these contact portions can be the areas of the valleys ofthe crimped textile structure. Other intermittent contact portions arealso contemplated. Current embolic coils require an internalstretch-resistant member to prevent stretching or unraveling during use.In the tubular textile structures disclosed herein. an internal stretchresistant member is not necessary since the risk of unwinding orunraveling of the internal element, e.g., radiopaque coil, is notpresent since the textile structure provides stretch resistance. Thus,the implant structure of the implants disclosed herein can be devoid ofsuch additional internal stretch resistant member(s). The absence ofsuch stretch resistant member inside the structure also provides anobstruction-free lumen so as not to interfere or inhibit blood flowthrough the distal end and through the lumen of the vascular graft.

The micrograft 10 is braided over the core mandrel which sets theinternal diameter (ID) of the braid. The core mandrel can be made of avariety of materials such as metal, wire, polymers or other textilefibers. It can also be formed of a stretchable material to aid inremoval during manufacturing.

The micrograft 10 in preferred embodiments can also include a permanentcore element such as shown in the embodiment of FIG. 4A discussed below.The core element can be made of a variety of materials, and can itselfbe formed of one or more filaments, and may optionally be coated. In onepreferred embodiment, the core element is formed of a metal coil havinga lumen therein. It can be composed of platinum-tungsten or othermaterials. The braid and coil can be heat set at a temperature thatwould not damage or disintegrate the braid.

The braiding process may be adjusted for the highest PPI possible so asto produce a tightly interlaced, dense braid without tenting (braidingover itself or overlapping). However, in some cases tenting may bedesirable to produce a useable feature such as a braid bulge or ring forlocking or wall thickening. The braid, while still mounted on the coremandrel, may be heat treated after manufacturing to set the braidstructure, including PPI, and to relieve filament stresses producedduring braiding.

The preferred PPI for the as-braided therapeutic structure, for example,may range from about 80 to about 200 PPI for a 16 strand braid, and morenarrowly in the range of about 120 to about 180 PPI, preferably about167 PPI. The PPI is dependent on the number of strands used to braid,the braid angle, and the braid diameter, such that a braided tube of agiven diameter with 120 PPI and 16 strands would have a PPI of 60 whenbraided using 8 strands at the same diameter (assuming all of thevariables constant). The preferred PPI should be high enough to producea dense interlacing pattern, but not so high as to interfere with coremandrel removal, unless the core is stretchable. Crimping, which will bediscussed later in detail, may be used to increase PPI (and braidangle), once again depending on final structural requirements.

The use of multi-filament yarns in combination with a relatively highPPI of the present invention results in a somewhat stiff, relativelysmall or closed cell (high pick density) braided tube. As mentionedabove, there is a micro-capillary effect resulting in wicking of liquidalong the porous yarns due to inter-fiber spaces and a macro-capillaryeffect resulting in liquid flow between yarns and throughout the textilewall due to inter-yarn porosity associated with using a wettablemulti-filament yarn. Due to the manufactured tube's relatively smallinner diameter and a sufficiently dense interlacing braid pattern (i.e.,a filamentary wall structure with sufficiently small pore size such thatit retains fluid), a third capillary effect is created. When properlysized, this third capillary effect is responsible for spontaneous flowof liquid inside the micrograft lumen, e.g., within the lumen of thebraid, in a proximal direction. In the embodiment of FIG. 4A whichincludes the inner element, the third capillary effect is through eitheror both a) the lumen of the inner element which is in the lumen of thebraid so the capillary effect is within the braid lumen; or b) in thegap between the inner diameter of the tubular braid and the outerdiameter of the inner element. The liquid can also spread in otherdirections as it is absorbed. This structure thus results in a softcapillary tube that has absorbent walls. This triple capillary effect isbeneficial for a vaso-occlusive device due to the fact that the yarns,the fibrous wall, and the micrograft lumen can become saturated withblood. Since blood absorbed by the micrograft is trapped within thestructure, it becomes stagnant and will quickly thrombose or form clot.In an exemplary embodiment, the inner diameter is preferably about0.003″ to about 0.012″, and more preferably about 0.007″.

To achieve the capillary and clotting characteristics, the micrograft 10achieves an optimal balance of porosity and fluid containment within thesame structure. This is achieved by controlled interlacing ofmicroporous yarns that allow blood wicking and cell ingrowth. Whenbraided with sufficiently high PPI and tension, for example, the porousyarns are able to form a fluid barrier that maintains a degree ofpermeability. The resultant structure (textile tube) is an assembly ofmicro-porous yarns that may be interlaced with sufficient density toform a fluid-tight tubular capillary. This interlacing of the yarns orassembly of filaments can be achieved using textile manufacturingprocesses, such as weaving, knitting, or electrospinning. Porous orsemi-porous filaments may also be used in place of multi-filament yarnsto achieve desired absorbency. Additionally, the micrograft structuredoes not have to include a clearly defined inside lumen to maintaincapillarity, e.g., a defined lumen formed within the wall of the braidor core element, but may alternatively be a porous assembly of fiberssufficiently spaced to allow transport of liquid (much like a suture orstring wicking liquid) or a porous scaffold or biocompatible open cellfoam.

While the semi-porous micrograft 10 as formed as described above has thedesired effect of aiding thrombus formation, it is also relatively stiffas a result of the filaments being closely packed or tightly braided asmentioned above. One benefit of a stiff, denser braid is its ability toretain its non-linear heat-set shape as compared with lower PPI (lessdense) braids. This may facilitate the use of stiffer, higher density 3Dshaped micrografts as framing-type devices used for initial filling ofaneurysm circumference, and then soft and highly compliant micrograftsmay be used as fillers or “finishing” devices towards the end of theembolization procedure. For example, a dense (or high PPI) 2×2(two-over-two) configuration braid may be used as the initial “framing”device whereas a softer and more compliant braid having a lower-PPI 1×2(1-over-2-under-2) configuration braid may be subsequently used to fillthe framed space within the first device. However, even if used as aframing device, excessive stiffness is an undesirable mechanicalproperty for the microcatheter delivery because an overly stiff devicemay cause unwanted movement of the microcatheter tip during deliverywhich can adversely affect navigation of the microcatheter or damagevessels during advancement through the tortuous vasculature. Excessivestiffness is also an undesirable property because stiff devices willconform less to the configuration of the aneurysmal sac and thus preventefficient aneurysm packing.

Therefore, to reduce stiffness to assist delivery and packing of theaneurysmal sac, the micrograft tubular body (braid) 12 is crimped duringmanufacture, i.e., longitudinally compressed and heat set. As the braid12 is compressed, axial orientation of the braided strands is reducedthereby increasing braid angle with respect to the longitudinal axis ofthe tubular body which reduces their influence on overall stiffness ofthe structure, much like a straight wire taking on a more flexible formwhen coiled. Crimping will also effectively increase the PPI, wallthickness, and linear density of the braid by axially compressing thestructure and filament bundles. This compression causes an outwardradial expansion and an increase in wall thickness of the tube. Theresulting braid is much more deflectable, has reduced bend radius, ahigher density and up to 2× to 3× or higher increase in PPI, dependingon braid structure and compressive force applied.

This axial compression also causes the braid structure to “snake” orproduce a spiral wavy form as shown in FIG. 1 , which as viewed from theside is a series of macro peaks and valleys, termed “macro-crimps” in asinusoidal shape. The sinusoidal undulations (macro-crimps) aretypically more pronounced in braid structures where the ratio of wallthickness to overall braid diameter is larger (i.e., overall diameterdecreases). Sufficient crimping may also re-orient individual yarn fiberbundles from a mostly flattened (longitudinally organized cross-section)state to a compressed (transversely organized cross-section) state. Thisincreases surface unevenness of the braid since individual yarns bulgeoutward and produce micro peaks and valleys on the braid surface, termed“micro-crimps” (see FIGS. 4B and 25B for example) with the peaks 17located at the height of the yarn and the valleys 19 between adjacentyarns.

The braid can have a series of coaxial aligned filaments and compressedso the filaments orient substantially transversely (with respect to alongitudinal axis of the mandrel).

Different braid patterns (such as 1×1, 1×2, or 2×2, etc.) may alsoproduce varied results when crimped. For example, a 1 x1 braid structurewill tend to have a more uniform tubular shape and less distinctivemacro-crimp pattern, whereas a 1×2 braid structure will produce a moresinusoidal (macro peaks and valleys) crimped structure in addition tothe micro peaks and valleys (micro-crimps) of individual fiber bundles.These structural changes result in an ultra-deflectable, increaseddensity, wavy-wall structure having macro-peaks 18 and valleys 20 asshown in the sinusoidal shape of FIG. 1 .

Besides increasing braid flexibility, PPI and/or wall thickness, varyingamounts of crimping imparts other potentially desirable features such askink and crush resistance, reduced bend radius, as well as increasedsurface area per unit length via accordion-like compression of the wall(i.e., forming peaks and valleys). The uneven texture of crimped peaksand valleys also helps create localized hemodynamic turbulence and flowstagnation, resulting in improved thrombus formation. The crimps makethe device more compliant, easily deflectable and conformable whichfacilitates packing confined spaces or voids in the vasculature, e.g.,the aneurysm. Crimping may also be used to vary wicking and permeabilityof the textile wall since it reduces fabric porosity and increases yarntortuosity.

The location, amount and magnitude of crimping can be controlled toimpart different amounts of flexibility and elongation to the structureto achieve its desired characteristics. For example, extreme crimpingcan be applied so the braid is compressed until the individual fiberswithin each yarn bundle come together and cannot compress any further,giving the braid some rigidity and improving pushability through amicrocatheter lumen. Other factors that impact crimping and theresulting longitudinal pattern are fiber diameter and stiffness, yarntension during braiding, wall thickness, wall porosity (PPI), number offilaments, and mandrel diameter.

For example, larger diameter, thin walled tubular bodies (braids), i.e.,low wall thickness to outer diameter ratio, may show macro peaks andvalleys which are more dense and visible than small, thick walledcrimped tubes. FIGS. 2A-2C show an example of such large diameter thinwalled tube where crimping can form an accordion-like folds or pleatstructure rather than a sinusoidal configuration as the peaks are closertogether. Crimping smaller diameter braids (braids with higher wallthickness to outer diameter ratios) typically induces a wave-like,sinusoidal longitudinal (macro) contour that is larger in comparison tooverall diameter and increases wall thickness of the structure, as shownin FIGS. 16A and 28B. It should be noted the sinusoidal contour istypically three-dimensional in form (like a spiral) and is visible fromall sides of the braid. During crimping, the ends of the tubular bodymay also be rotated/twisted relative to each other and then heat set asanother method to impart deflectability to the tubular body.

The crimps are produced by compressing the textile tubular structureaxially to reduce length and thereby produce a longitudinally extendingwavy shape. The crimping reduces an axial orientation of the fibers toincrease a braid angle and increase a linear density and wall thicknessby axially compressing the biocompatible tubular structure, and forms aseries of alternating peaks and valleys along a length of a surface of awall, i.e., in a longitudinal direction along the longitudinal axis, toform a longitudinally extending wavy sinusoidal shape. In someembodiments, crimping can increase the braid angle by at least 5degrees. In other embodiments crimping can increase the braid angle bybetween 1 and 4 degrees. For example, in some embodiments, the braidangle pre-crimping can be between 1 degree and about 40 degrees and thepost crimping angle can be between about 35 degrees and 90 degrees.Other angles are also contemplated.

The braid 10 can also be made more flexible by varying the braid angleor PPI, by reducing yarn tension, by adding cuts/slits, changing thenumber of filaments or strands, or heat setting repeating patterns alongits length (such as flat sections or kinks). If a stiffer tube isdesired, denser yarn and/or braid pattern may be used or crimpingdecreased. Additionally, the micrograft structure may incorporate acoaxial construction (i.e., having a graft inside a graft) or multi-plyor multi-lumen wall design, especially when using fine-denier textiles.Intra-luminal braid inserts, such as the coils mentioned above, may alsobe composed of, or coated with, a highly wettable/hydrophilic materialto enhance the capillary effect. For example, the micrograft may becoaxially assembled with a secondary braid or internal coil structurethat is highly hydrophilic and/or radiopaque, while maintaining thetherapeutic external surface.

The tubular body 12 may be braided, woven or knitted, partially orcompletely, from monofilaments or multi-filament yarns, strands,sutures, microfibers, or wire that is synthetic, semi-synthetic, naturalor thermoplastic. Such materials may include, but are not limited to,Dacron, poly ester amide (PEA), polypropylene, olefin polymers, aromaticpolymers, such as liquid crystal polymers, polyethylene, HDPE (highdensity polyethylene), ultra-high-molecular-weight polyethylene (UHMWPE,or UHMW), polytetrafluoroethylene (PTFE), ePTFE, polyethyleneterephthalate (PET), polyether ketone (PEK), polyether ether ketone(PEEK), poly ether ketone ketone (PEKK), nylon, PEBAX, TECOFLEX, PVC,polyurethane, thermo plastic, FEP, silk, and silicone, bio-absorbablepolymers such as polyglycolic acid (PGA), poly-L-gllycolic acid (PLGA),polylactic acid (PLA), poly-L-lactic acid (PLLA), polycaprolactone(PCL), polyethyl acrylate (PEA), polydioxanone (PDS) and pseudo-polaminotyrosine-based acids, extruded collagen. Metallic, metallic alloy orradiopaque material may also be included, Such material may be in theform of strands or filaments and may include, for example, platinum,platinum alloys (platinum-iridium or platinum-gold, for example), asingle or multiple stainless steel alloy, nickel titanium alloys (e.g.,Nitinol), barium sulfate, zinc oxide, titanium, stainless steel,tungsten, tantalum, gold, molybdenum alloys, cobalt-chromium,tungsten-rhenium alloys.

In preferred embodiments, the textile structure is formed of fibers ofnon-absorbable material such as the non-absorbable materials (materialswhich do not have a medical indication for the material to be absorbedinto the tissues or absorbed by the human body) listed above.

The use of different manufacturing methods or materials to construct thetubular body may have an impact on the capillary effects discussedearlier. For example, a change in material or construction methods mayresult in a simple capillary tube with capillary flow restricted to onlythe inner lumen of the tube, and not the walls. It should be understoodby those skilled in the art that strands or filaments may be braided,interwoven, knitted, or otherwise combined to form a fabric or textilestructure.

With reference now to the drawings showing exemplary embodiments of themicrograft of the present invention, the micrograft 10 of FIG. 1 , asdiscussed above has a tubular body 12 with a proximal end 14 and adistal end 16.

To provide radiopacity so the device is visible under fluoroscopy(x-ray), the micrograft 10 can include radiopaque structures such asradiopaque marker bands 22 which are inserted into the ends of themicrograft 10. FIG. 17 is a picture of an end of micrograft 10 with suchmarker band. The marker bands, which can also be in the form of coils orspheres, can be made from tantalum, platinum, platinum alloys (e.g.,platinum-iridium alloy), gold, tungsten, or any suitable radiopaquematerial such as radiopaque polymer. The marker bands 22 are preferablyapproximately 1 mm or less in length and can be either of a sufficientinner diameter to slide over tubular body 12 or of a smaller diameter tofit inside the tubular body 12. FIG. 1 shows an example of the markerbands 22 fit inside the tubular body and the marker bands 22 can besecured by melting of the braid over the bands (the melted fiber) atregion 24, or attached by gluing. The bands 22 can also be undersizedand sliced lengthwise so that they can be swaged or folded over theoutside of tubular body 12, or tubular body 12 can be stretched so thatundersized bands can be slid over the stretched/compressed length inorder to attach the bands 22 to the tubular body 12. In alternateembodiments, the bands can be flared at one end.

Although two marker bands are shown, in alternate embodiments, there maybe one band or more than two bands placed around the tubular body alongportions of its length to improve radiopacity. The bands positionedalong the length can be in lieu of or in addition to a marker band atone end or a marker band at both ends. A radiopaque fiber can beutilized to connect the bands, and the radiopaque fiber incorporatedinto the textile structure, or placed inside the tube. The bands can becomposed of metal, or alternatively of a non-metallic material such asradiopaque shrink tubing or polymer.

The marker bands can be adhered to the tubular body 12 using adhesive,mechanically by swaging or winding directly on to the tubular body, orby heating (when possible) and melting one of the materials. The bandscan alternatively be attached by being screwed onto or into the coreelement, e.g., a helical core element, as discussed below.

In an alternate embodiment, radiopaque balls or spheres can be putinside the braid lumen to provide radiopaque structure. This providesthe radiopacity while providing a less stiff, i.e., more deflectable,device. The balls or spheres can be spaced apart axially along thetubular braid, or alternatively one or more can be in contact with oneanother, and can be either as an addition to the radiopaque coil and/ormarker bands or as an alternative. The coils and spheres can be made ofthe foregoing materials utilized for the marker bands.

As an alternative or in addition to the marker bands, radiopacity can beobtained by coating, wetting, staining, or impregnating the micrograftwith a radiopaque material such as contrast media solution ornanoparticles. This can be done in manufacturing or in the operatingroom as part of the clinical procedure. The fibers or yarns themselvesmay be doped or impregnated or coated with radiopaque substances asdescribed above. The micrograft may also contain a series of equallyspaces radiodense inserts along its length, resulting in intermittentradiopacity which may be sufficient for visualization in clinicalsettings.

In addition to providing radiopacity, bands 22 can also be used toindicate structural changes in tubular body 12, as a means to controlfraying, or as an integral part of the delivery system (e.g.,stop-collar) as will be better understood in the discussion below of thedelivery of the micrograft.

As another alternative to the bands, laser cut Nitinol structures thatare made increasingly radiopaque can be utilized. These structures canbe glued, melted over, sewn or otherwise attached to the proximal and/ordistal ends of the micrograft, either on the inner or outer diameter,and/or attached along a length of the tubular body. Sections of themicrograft or meltable/fusible sleeves of a braided polymer may also beheated and used to adhere bands or other radiopaque structures(components) to the micrograft. Bands or other radiopaque components canalternatively be attached by screwing into the coil windings inside thebraid as discussed in more detail below. The bands or other radiopaquecomponents can either be self-expanding or non-self-expanding. Whenmated with the delivery wire and pusher catheter described below, theycan serve to control micrograft linear movement relative to the wire.

As an alternative to the bands or other radiopaque structure forproviding radiopacity, a radiopaque agent as described above could beutilized which would allow complete visualization of the full length ofthe graft. Another way to provide visualization is the inclusion of aradiopaque coil or insert across the entire length of the inner lumen ofthe micro-graft. The addition of such coil would make the entire lengthof the graft radiopaque, however, preferably, to avoid such coil addingan unwanted increase to the structure's radial stiffness, and tominimize such stiffness while maximizing x-ray visibility, such coil maybe wound using very thin wire typically not visible via fluoroscopy, butwhen coiled with sufficiently small pitch (spacing between each loop) itbecomes increasingly dense and visible. Pitch of the coil may also varyto make some sections more radiopaque or flexible than others. The coilcan be made of materials such as platinum, platinum-iridium, tantalum,gold, silver or other radiopaque materials used for medical devicevisualization. The coil can have a continuous diameter or variablediameter along its length, depending on use. The coil can also be usedin combination with radiopaque bands, coatings or as a stand aloneradiopaque solution. Insertion of such coils inside the micrograft mayalso reduce the amplitude of macro-crimps formed during crimping ifdesired, depending on radial apposition of coil to braid. It should alsobe noted that coils or other internal inserts may be partially visiblethrough the braid wall depending on the amount of crimping, although ina preferred embodiment, the braid is closed cell, defined herein as theinner coil not being visible between braid strands or not being directlyvisible through gaps of the braid. However, in a preferred embodiment,the closed cell configuration still has sufficient spaces between theyarns and filaments for blood flow as discussed herein.

If needed, a simple “J” shape can be heat set into tubular body 12 toaid with introduction into the aneurysm. Agents may also be added to thetube to aid in delivery and/or endothelial cell growth. For example, ahydrophilic coating can be applied to the surface of tubular body 12 toaid in delivery through a microcatheter or a swellable hydrogel infusedwith drugs can be added to provide medicinal treatment and additionalfilling of the aneurysm. Another example is a clotting agent which maybe added to either slow or inhibit the clotting process or to promoteclot formation. Bio-absorbable and biocompatible fibrous elements suchas Dacron (polyethylene terephthalate), polyglycolic acid, polylacticacid, a fluoropolymer (polytetrafluoroethylene), nylon (polyamide) orsilk can also be incorporated into the braid, or to the surface, toenhance the ability of the tubular body 12 to fill space within thevasculature and to facilitate clot formation and tissue growth.Similarly, hydrogels, drugs, chemotherapy beads and/or fibers can beadded to the inner diameter of tubular body 12 or infused into thewalls, yarns, or fibers depending on specific use (for example embolicchemotherapy). On the finishing side of the micrograft (proximal end), amicrocoil (not shown) may be added to provide a barrier between theaneurysm sac and the parent vessel. FIG. 1 can include similar featuresor functions as will be described below.

FIGS. 2A-2C illustrate a micrograft similar to micrograft 10 of FIG. 1except having a larger diameter and thinner wall. FIG. 2A illustratesthe thin walled micrograft 25 crimped in the process described above toforms peaks and valleys resulting in circumferential corrugations orfolds. FIG. 2B is provided for illustrative purposes to highlight thepeaks and valleys by stretching the tubular body. FIG. 2C shows aportion of the micrograft 25 in the bent position. In some embodiments,the micrograft is pre-set in this bend, e.g., a U-shaped configuration,to improve packing within the aneurysmal sac. As shown, due to thestructure of the micrograft, when bent, it maintains its radius in thesimilar manner to a bent coil. (The micrograft would be delivered in asubstantially linear position as described below). As shown, thecompression and heat setting (crimping) process creates an “accordionlike” structure with peaks 18′ and valleys 20′. In FIGS. 2A-2C, the wallof the micrograft 25 is a fine braid, or textile structure, and willapproximate a solid structure when placed in direct blood flow, causinghigh flow disruption. Another feature of the graft is its white color,which may vary depending on PET formulation and processing. If desired,colors other than white may be used to denote different body diametersor transitions in mechanical or therapeutic properties, for example.

Note crimping alters the direction/orientation of the yarns/filamentswith respect to a longitudinal axis of the tubular braid. In someembodiments, after crimping, the yarns/filaments are substantiallytransverse to the longitudinal axis. In other embodiments, theyarns/filaments after crimping are at about 35 degrees to thelongitudinal axis, or between about 35 degrees and about 90 degrees. Inalternate embodiments, the yarns/filaments after crimping are at about45 degrees to the longitudinal axis, or between about 45 degrees andabout 90 degrees. The effect of crimping is to increase the angle of theyarn or filament relative to the longitudinal axis, i.e., if theuncrimped braid angle is X degrees with respect to the longitudinalaxis, the braided angle when crimped is X+Y degrees. In preferredembodiments, Y>5 degrees, although other values of Y are alsocontemplated. It is understood to those familiar in the art that braidangle relative to longitudinal axis (typically referred to as the alpha(α) angle) is measured while braided structure is in a straightorientation, however, the angle may also be measured between crossingyarns or filaments (typically referred to as beta (β) angle) in whichcase the value would be double (2× degrees) as exemplified in Figurediscussed below (compare angles B and C).

In relation to braided structures described herein, for example, tubesbraided with 16 ends (yarns) and braid angles above 40 degrees (relativeto longitudinal axis) become increasingly challenging to process, aremuch stiffer, and increased friction between the tight braid and mandrelhinders removal of the mandrel from inside the braid. As a result, suchbraids are typically manufactured with braid angles below 40 degrees.For tubes braided with 12 or 8 ends for example, the typical maximum abraid angle is even lower, around 30 degrees. Crimping, therefore, asdisclosed herein, as a secondary process, allows increase of PPI andbraid angle while maintaining softness/conformability/flexibility.

Crimping increases the amount of thrombogenic (fiber) surface exposed tothe body. That is, crimping increases the amount of fiber material perunit length as the length of the braid decreases and the diameterincreases. In some embodiments by way of example, the length of thetubular body can decrease as a result of crimping by about 50%, althoughother decreases in length are also contemplated.

FIGS. 4A, 4B, 4D and 4E-4M show an alternative and preferred embodimentof the micrograft, designated generally by reference numeral 10′.Micrograft 10′ is similar to micrograft 10 as it formed from a braidedtube 12′ and has the same features and functions of tube 12 as well ascan include any of the alternate braid constructions described herein.Thus, the various descriptions herein of the filaments, yarns, capillaryeffects, shape set, etc., are fully applicable to the micrograft 10′ ofFIG. 4A. However, micrograft 10′ has a core element 27, preferablyformed by a helical coil, having a lumen for blood flow in theaforementioned capillary effect. The coil is formed into a helical shapeand has a proximal end 27 a (FIG. 4F) and a distal end 27 b. Lumen 27 cextends through the coil 27 from the proximal end 27 a to the distal end27 b. In a preferred embodiment, the coil 27 is composed of a metal suchas platinum or a platinum tungsten alloy. In manufacture, the textilestructure in the form a tubular braid 12′ is positioned over the coil27. That is, the braid is formed separately into a tubular shape with alumen or longitudinally extending opening 39 extending from the proximalend to the distal end for receipt of the coil 27. The braid 12′ ispreferably composed of PET or other thrombogenic material. The braid 12′can be in the forms disclosed herein and is preferably substantially aclosed cell design to provide a large percentage of outer surface areafor contact with the blood and/or vessel/aneurysm wall. However,although generally a closed cell design, it has spaces between the yarnsand filaments as described herein to enable blood flow into and/orthrough the device. Such flow achieves the capillary effects describedherein. This configuration promotes tissue ingrowth in a relativelyshort amount of time, and in some instances within 30 days ofimplantation. The micrograft 10′, with braid 12′ and attached inner coil27, is formed into a helical coil shape as shown in FIG. 4K with a lumen39 extending along its length.

As discussed herein, the braid is preferably crimped to increase thebraid angle and increase softness, compressibility and amount ofthrombogenic surface area in the device. The structural effect of suchcrimping can be appreciated by the comparative views of FIGS. 25A-28B.FIGS. 25A and 26 a show the braid 12′ before crimping wherein the braid12′ has an angle A with respect to the longitudinal axis L of thetubular braided textile structure 12′. FIGS. 25B and 26B illustrate thebraid 12′ after crimping where the braid 12′ has an angle B with respectto the longitudinal axis L of the tubular braided textile structure12′which is greater than angle A. Angle C of FIG. 25C depicts thealternate way to measure braid angle by measurement between crossingfilaments.

The aforedescribed spacing between the filaments and yarns, and theresulting capillary effects can be appreciated with reference to FIGS.4L and 4M. Filaments or fibers 33 have spaces or gaps (voids) 34therebetween for blood absorption and flow. Yarns 31 (fiber bundles)composed of filaments 33, have spaces or gaps (voids) 37 therebetween.These create the aforedescribed first and second capillary effects. Thelongitudinal opening 27 c extending through the braid inner coil 27 andoverlying braid 12′ (FIG. 4J) creates the third capillary effectdescribed above.

This configuration of the embodiment of FIG. 4A also encourages rapidblood clotting and in some instances clotting can occur immediately uponimplantation. In fact, in this configuration, when the micrograft(implant) 10′ is held in the delivery system within the vessel/aneurysmbut prior to release from the delivery system, the micrograft 10′becomes filled partially or entirely with blood so that blood stagnationcan commence even before the micrograft 10′ is released and implanted,thereby expediting thrombus formation. Saturation of the micrograft inthe delivery assembly and once implanted accelerates and/or improvesthrombosis.

Note the braid fibers are not only thrombogenic (attract blood plateletsand proteins which promote clot) due to their material, e.g., PET can beused as the filaments or as a thrombogenic surface, but also promotestasis as the braid structure traps blood.

In the embodiment of FIG. 4A, a tube 29, preferably composed of Nitinol,although other materials can be utilized, is seated within proximalcoils of the helical core element (coil) 27, preferably screwed ortwisted into the proximal coil windings of the helical core element 27to provide structure for engagement with a delivery device. The braid ismelted onto tube 29, with region 24 a showing the melted fibers, toattach the tube 29. As illustrated, the tube 29 (or tubes 29′, 29″,29′″) extends proximally of the core element 27. It also extendsproximally of the tubular textile structure 12′ so a proximal region isexposed for engagement by a delivery member. A distal portion of thetube 29 is within the tubular textile structure. The formation ofthreads in the tube 29 for attachment to the core element windingsallows the textile structure, e.g., braid, to melt into the threads,thereby further stabilizing/reinforcing the attachment of the outertextile structure 12 to the inner elements. That is, the cut feature inthe tube 29 provides a better joint (increased bond strength) betweenthe textile structure 12′ and the tube 29′ as the melted material(textile structure) flows into the spaces between the threads. It iscontemplated that instead of threads, laser cut holes or tabs or otherengagement features can be provided to attach the tube to the inner(core) element by screwing into, pressing into or other methods ofinterlocking. That is, these engagement features, e.g., cut features orsurface gaps, can be used instead of threads for twisting into or otherattachment of the tube to the proximal coils of the core (inner) elementand such features can also be provided to receive the melted material(textile structure). It is also contemplated that other laser cutfeatures such as holes or surface gaps can be made in the tube toprovide additional spaces for the melted material to increase thestrength of the attachment These additional spaces can be in addition tothe features for attaching the tube to the inner element. In someembodiments, tube 29 has a deflectable tab 29 a and a window 29 b toreceive a delivery wire as described below in conjunction with thedelivery method. The tab 29 a is biased to the aligned position of FIG.4B and is moved to an angled position to receive the wire through thewindow 29 b, the tab 29 a providing an engagement/retaining structurefor engagement with a wire of a delivery system described below. Region24 b (FIG. 4F) illustrates the region at the proximal end where thefibers of braid 12′ are melted onto the proximal end of coil 27. Note inFIG. 4F an alternative tube configuration is illustrated, with tube 29′having a slot to receive a ball or hook as in FIG. 22A. In FIG. 4G,electrolytic detachment of the implant is disclosed with wire 230 heldwithin tube 29′ by epoxy 232 or other material to which it is attached,e.g., glued or fused. The material 232 provides an insulator to ensurethe wire 230 is not in contact with the tube 29′. Except for the tube 29and electrolytic detachment, the micrografts of FIGS. 4F-4H areidentical to micrograft 10′ of FIG. 4A. Tube 29′ can be screwed into thecoils of core element 27 in the same manner as tube 29. It should beappreciated that tubes 29, 29′ (and electrolytic detachment) can be usedwith the braid of FIGS. 4A-4M as well as with any of the othermicrograft and braid embodiments disclosed herein.

As noted above, braid (braided tube) 12′ is made up of yarns 31 eachcontaining multiple fibers 33. When removed from the braider, theyarn(s) 31 of tube 12′ will lay relatively flat with the fibers 33bundled horizontal and spaced apart (see FIG. 4D showing tube 12′positioned over mandrel 35). FIG. 4E illustrates the braided tube 12′which has been crimped over mandrel 35 to create crimped braided tube12′ prior to formation into the structure of FIG. 4A. This is alsodescribed below in conjunction with the method of manufacture. When thebraid 12′ is fixed to the mandrel 35 (FIG. 4D at one or more points anda longitudinal force is applied to the braid, the fibers 33 in the yarn31 will move closer together and bundle vertically creating micro peaks17 and micro valleys 19 between peaks 17 (FIGS. 4E and 25B) andcorresponding macro peaks 18 and macro valleys 20 along the tube lengthcreating a sinusoidal shape (FIGS. 4E and 28B). (The peaks and valleysof the FIG. 1 embodiment disclosed herein can be formed in a similarmanner). The extent of the peaks and valleys is dependent on the amountof force applied and the desired amount of softness. The tube can becompletely crimped or selectively crimped at intervals along its length.

In an exemplary embodiment, the inner diameter of the tubular braid 12′is preferably about 0.003″ to about 0.012″, and more preferably about0.007″. The coil 27 can have an inner dimeter of about 0.002″ to about010″. In some embodiments, the coil can have an inner diameter betweenabout 001″ to about 0.002″ less than the inner diameter of the braid. Inother embodiments, the coil can have an inner diameter greater than theinner diameter of the tubular braid since the braid expands in diameterupon crimping.

FIGS. 4N, 4O and 4Q illustrate alternate embodiments of the devicehaving an optimized joint between the outer polymeric structure andinner element. A balance needs to be achieved in the overall devicebetween the stiffness of the device to maintain its heat set shape andthe softness/flexibility of the device to avoid damage to thevasculature and to enhance aneurysm packing. Additionally, inmanufacture, in attaching the components of the device, i.e., the outerpolymeric structure, e.g., a textile structure such as theaforedescribed braid, and the inner element, e.g., a radiopaque coilsuch as the aforedescribed metal coil, a balance needs to be maintainedbetween sufficient stiffness and flexibility. Additionally, at the jointwhere the polymeric structure and inner element are attached, thebalance needs to be obtained between a sufficiently long length of thejoint to enable a secure connection between the outer polymericstructure and the inner element and a sufficiently short length so thatit does not create undue stiffness. If the connection, i.e., joint, isof insufficient length, it will be too weak and the polymeric structureand inner element could separate during delivery through tortuousvasculature and/or in use/placement within the aneurysm. However, if theconnection, i.e., joint, is too long and thereby too stiff, it could behard to deliver and in some instances possibly undeliverable throughtight turns in tortuous vessels and could also increase the risk ofrupturing the aneurysm. Additionally, if too stiff, it could adverselyaffect the curvature of its secondary shape. Moreover, since the jointhas a solid (non-porous) outer surface, it prevents tissue ingrowth.Therefore, the longer the attachment (connection), the less surface areaof the implant available for tissue ingrowth. Stated another way, theadvantages of a shorter joint are that it reduces the stiffness of thedevice and maximizes the area for tissue ingrowth. However, the jointmust be long enough to maintain attachment of the components/materials.

As shown in the embodiment of FIG. 4N, the implant 300 is identical toimplant 10′ of FIG. 4F except for the joint. As used herein, the termjoint denotes the connection or attachment of the outer polymericstructure, i.e., the braid, to an internal (inner) component, i.e., theradiopaque coil and/or metal tube, within the braid. The joint can be anattachment formed by application of energy to bond thematerials/components, formed by an adhesive attachment, formed by amechanical bond, or formed by other methods. Examples of use of energyinclude heat (for melting), ultrasound, laser and electric current. Notethe biocompatible polymeric structure can be a textile structure formedby manufacturing processes such as weaving, knitting, and braiding ormay be a porous structure made by electrospinning or extrusion. Thepolymeric structure is porous, i.e., has spaces to maintain porositywhich can let air or gas through and in preferred embodimentssufficiently spaced to let in blood. In the illustrated embodiments ofFIGS. 4N-4Q, the polymeric structure is a textile structure in the formof a braid composed of a plurality of filaments and a plurality of yarnsas discussed herein. Note the inner element is in the form of a coil,preferably radiopaque, and can be made of a polymer or metal.

As shown in FIG. 4N, region 324 denotes the distal joint formed bymelting the fibers of the textile structure, i.e., the braid, onto theinner coil, i.e., the radiopaque metal coil. In a preferred embodiment,the distal joint 324 extends for a length L1 between about 0.002 inchesand about 0.050 inches. In a more particular embodiment, the distaljoint 324 extends for a length of between about 0.004 inches and 0.020inches. Note that other lengths are also contemplated, however, theforegoing ranges optimize the joint length by obtaining the minimumlength for secure attachment without unduly sacrificing flexibility orsufficient tissue ingrowth.

In certain embodiments, the distal joint 324 covers at least twowindings (also referred to as wire loops or rings) of the inner element327, shown in FIG. 4N as a metal coil similar to metal coil 27 describedherein. It has been found in some embodiments that covering, e.g.,attachment, to two coil windings achieves the desired balance/objectivesdescribed above. In FIG. 4N, the inner metal coil 327 extends to thedistal end of the textile structure 12 which is in the form of a braidin FIG. 4N. In this embodiment, distal joint 324 covers two coilwindings 327 a, 327 b, which are the distalmost windings of coil 327.Note an additional radiopaque coil 328 can be positioned within thedistal coils of metal coil 327 to provide a closed pitch and alsoenhance radiopacity for imaging of the distal portion of the implant300. An optimal melt joint will fuse at least two coil windings of asingle coil or at least one coil winding from each coil when two coilsor helical elements are being joined together.

In the alternate embodiment of FIG. 4O, implant 400 has an inner coil427, which is a metal coil similar to coil 27, that extends a furtherdistal distance beyond the distal edge of the textile structure 12(which is in the form of a braid). In this embodiment of FIG. 4O, thedistal joint 424 extends from the distalmost part of the textilestructure 12 to cover two coil windings 427 a and 427 b, which arespaced proximally from the distalmost coil winding 427 c of the innerelement 427. A small weld joint 427 d at the distalmost end joins thecoils together. The distal joint 424 extends from the braid to a portionof the inner element 427 spaced proximally from its distalmost end.(Note a stretch resistant element can be provided attached to the distalend of the coil 427 and extending its length). The distal joint 424,like distal joint 324 of implant 300 of FIG. 4N, extends for a length L3between about 0.002 inches and about 0.050 inches, and in a moreparticular embodiment for a length from about 0.004 to about 0.020inches. Note that other lengths are also contemplated, however, theforegoing ranges optimize the joint length by obtaining the minimumlength for secure attachment without unduly sacrificing flexibility orsufficient tissue ingrowth. FIG. 4O also differs from FIG. 4N at theproximal joint which is discussed in detail below. In all otherrespects, the embodiment of FIG. 4O is the same as the embodiment ofFIG. 4N. Note implant 400 can also include an additional radiopaque coil428 positioned within the distal coils of metal coil 427 which providesa closed pitch and also enhances radiopacity for imaging of the distalportion of the implant 400. The exposed length of the radiopaque coildistal of the distal joint 424 can be closed pitch as shown.

Referring back to FIG. 4N, at a proximal end, region 330 denotes theproximal joint formed by melting the fibers of the textile structure,i.e., the braid, onto the metal tube 329 which is the same as metal tube29 of FIG. 4A. Tube 329 can be screwed into the proximal coils of innerelement 327 in the same manner as discussed above with respect to tube29 or attached by other methods. In the alternate embodiment of FIG. 4Q,region 370 denotes the proximal joint formed by melting the fibers ofthe textile structure onto the metal tube 379 (which is the same as tube329) and at least one coil winding of inner coil element 377. In allother respects, the vascular implant of FIG. 4Q is the same as thevascular implant 300 of FIG. 4N. In a preferred embodiment, the proximaljoint 330 (and 370 of FIG. 4Q) extends for a length L2 between about0.002 inches and about 0.050 inches. In a more particular embodiment,the proximal joint 329 extends for a length of between about 0.004inches and 0.020 inches. Note that other lengths are also contemplated,however, the foregoing ranges optimize the joint length by obtaining theminimum length for secure attachment of the braid 12 and tube 329 (ortube 379 and inner element) without unduly sacrificing flexibility orsufficient tissue ingrowth. The proximal joint can be formed by thevarious methods described herein, e.g., energy application, adhesive,mechanical bonding, etc.

Note in the embodiments of FIGS. 4N, 4O and 4Q the distal joint isformed by heating the braid to form a melt joint with the inner metalcoil 327, 427, 377, respectively. In the embodiment of FIG. 4N, theproximal joint 330 is formed by heating the braid to form a melt jointwith the metal tube; in the embodiment of FIG. 4Q, the proximal joint isformed by heating the braid to form a melt joint with the metal tube andthe inner coil; and in the embodiment of FIG. 4O, the proximal joint 430is formed by heating the braid to form a melt joint with a proximalregion of inner metal coil 427, e.g., the two proximalmost coil windingsof inner coil 427, since the metal tube is not provided. The proximaljoint 430 preferably has a length L4 as described above with respect tolength L2 of FIG. 4N. Note that the distal joint of FIGS. 4N, 4O and 4Qcan be utilized with the proximal joint of FIG. 4N or 4O depending onwhether a metal tube or other helical element is provided at theproximal end of the inner metal coil.

Note the melt joint preferably covers a width of the yarn of the braid.As noted above, the joint 324, 424, 330, 370 and/or 430 can be formedother than by heating such as by vibrational methods, adhesive, etc.

In the embodiments of FIGS. 4N, 4O and 4Q, the distal joint 324, 424,respectively, is continuous along a length. Similarly, in theillustrated embodiments of FIGS. 4N, 4Q and 4O, proximal joints 330, 430370, respectively, are continuous along their length. However, it isalso contemplated that the distal and/or proximal joint of theseembodiments be non-continuous. This is illustrated for example in theembodiment of FIG. 4P wherein the distal joint 524 is formed by aplurality of discrete spaced apart (non-continuous) sections. As shown,joint 524 is composed of discrete melted (or alternatively welded oradhesive) areas along a length L5 of between about 0.002 inches andabout 0.050 inches. In a more particular embodiment, the distal joint524 extends along a length of between about 0.004 inches and 0.020inches. Stated another way, the distance from the proximalmostattachment of the textile structure 12 and inner coil 527 to thedistalmost attachment of the textile structure 12 and inner coil 527 ispreferably within these ranges. Note that other lengths are alsocontemplated, however, as noted above, the foregoing ranges optimize thejoint length by obtaining the minimum length for secure attachmentwithout unduly sacrificing flexibility or sufficient tissue ingrowth.Note the proximal joint 530 (attaching the braid 12 to the proximal coilwindings or alternatively to a metal tube like tube 29) can also benon-continuous like the distal joint 524. In the embodiment of FIG. 4P,two spaced apart attachments A1 and A2, e.g., melts or welds, areillustrated, it being understood that additional attachments, e.g. meltsor welds, can also be provided. Other spaced ways of attaching, e.g.,adhesive, are also contemplated.

In an alternate embodiment, a mechanical joint can be utilized insteadof a heat or adhesive joint. That is, a band, preferably composed ofmetal, can be swaged or otherwise mechanically attached to the braid.The length of the band is preferably between about 0.002 inches andabout 0.050 inches to achieve the advantages enumerated above associatedwith these lengths. In a more particular embodiment, the metal bandextends for a length of between about 0.004 inches and 0.020 inches.Note that other lengths are also contemplated, however, the foregoingranges optimize the band length by obtaining the minimum length forsecure attachment without unduly sacrificing flexibility or sufficienttissue ingrowth due to the non-porous outer wall of the band. The metalband can have a continuous outer wall of the foregoing lengths ornon-continuous outer wall (e.g., axially spaced bands) of the foregoinglengths to satisfy the above balance of competing factors regarding itslength. A band can be provided to form a mechanical distal joint at adistal end of the implant and/or a mechanical proximal joint at aproximal end of the implant.

As can be appreciated, the aforedescribed proximal and distal joints,with their respective optimized lengths, can be utilized with the otherembodiments of implants disclosed herein.

Note as used herein, the phrase “about” means plus or minus 10% of thenumeric value.

In the alternate embodiment of FIG. 29 , the implant 350 includes twopolymeric structures 352, 354 attached at a proximal end. The twopolymeric structures can be any of the polymeric structures, such as thebraided structure, with an inner element, e.g., a radiopaque coil suchas a metal coil, positioned herein. The polymeric structures can havethe distal and/or proximal joints discussed above to avoid unduestiffness. The polymeric structures 352, 354 are shown attached at theirproximal ends to a radiopaque element, e.g., a coil or marker band 356and are unattached at their distal ends. A radiopaque element, e.g., acoil or distal marker band 357, 358, can be provided at their distalends. In alternate embodiments, the polymeric structures 352, 354 arejoined at their distal ends by a radiopaque element such as a coil ormarker band. Thus, the polymeric structures 352, 354 can be joined by aradiopaque element at their proximal end and/or their distal end. Theside-by side double braid configuration provides a more efficientpacking of the aneurysm. It can also save procedural time by enablinginsertion of two braids simultaneously. Note that any of the implantsdisclosed herein can be provided as a double structure as in FIG. 29 toobtain these advantages.

In the alternate embodiment of FIG. 4C, instead of a locking tab, amarker band 22′ is attached to the tube to provide retention structurefor engaging structure on the delivery wire. In all other respects, themicrograft of FIG. 4C is the same as the micrograft 10′ of FIG. 4A andhas therefore been labeled with the same reference numerals.

The braid of the implant is preferably non-expandable. That is, afterformed, a dimension measured through a transverse cross-section of theimplant (braid and coil) is the same in a delivery position within adelivery member as in the placement position. The implant, however, maybe stretched to a reduced profile position for delivery and thenreleased for placement to assume its coil shape discussed above.However, when it moves from the delivery to the placement position, thebraid does not expand. The change is to the implant (braid and coil)from the linear shape within the delivery member to its secondaryhelical shape within the body, but the combined thickness of the braidand coil (i.e., the outer diameter of the braid) remains constant duringdelivery and placement. This is in contrast with expandable braidswherein the diameter of the braid increases when exposed from thedelivery member and in the placement position. As discussed herein, suchexpansion increases the inside diameter of the braid and at least ininitial expansion or expansion to a certain percentage, can increasepore size (openings) in the braid.

The method of manufacturing the implant of FIG. 4A will now bedescribed. Note in the method, the braid is formed separately into atubular form and then the coil is positioned within the braid beforeheating and melting of the braid onto the coil. Thus, as can beappreciated, the braid is not wound onto the coil but is formedseparately and the two elements/components (structures) subsequentlyattached.

Set forth below is one example of a manufacturing method that can beutilized to make the vascular implant (micrograft) of FIG. 4A, it beingunderstood that other methods can also be utilized. Additionally,different implant structures are disclosed herein which could entailother manufacturing methods. The steps of an exemplary manufacturingmethod are as follows.

1) The braid (formed by the aforedescribed filaments) is formed on amandrel. Note the braid in a preferred embodiment is composed of PET,although as noted above, other materials are contemplated. (Note that asdiscussed herein, the textile structure can alternatively be in the formof a woven textile structure, an electrospun structure formed from oneor more polymeric fibers, or other overlapping fiberarrangements/structures formed into a tubular shape as in step 2 below).

2) The braid is relaxed and annealed to set into a tubular shape(tubular structure).

3) After cooling, the tubular braid is compressed on the mandrel tocrimp the braid, increasing the amount of fiber per unit length and/orin certain embodiments forming peaks and valleys as described above.Note when the tubular braid is compressed, the inner coil is not withinthe braid, so that the crimping does not affect the coil.

4) The tubular braid is heated again to set in the compressed state.

5) After cooling, the braid is removed from the mandrel to ready forattachment to the inner element, i.e., the metallic coil.

6) The metallic coil is formed by winding a wire about a mandrel into ahelical shape, and the opposite ends of the coil wire are attached,e.g., glued, in tension around the mandrel. The tensioned metallic coilis positioned within the tubular braid, i.e., inserted into the tubularbraid or the tubular braid is slid over the tensioned metallic coil,which in either case means the metallic coil is “insertable into” thebraid. Note in this tensioned position, the metallic coil is tightlywound around the mandrel and of a reduced height (the height defined asthe diameter or transverse dimension measured from a topmost point alongthe length to a bottommost point along the length of the coil). As notedabove, the coil wire in a preferred embodiment is composed of platinumalloy for radiopacity, although other radiopaque materials can also beutilized.

7) Once within the tubular braid, the attached glued ends of thetensioned coil are cut, causing the coil to slightly spring back andunwind, resulting in some expansion (increase in overall coil diameter)toward the braid, with portions of the coil coming into contact with thebraid. Note in some embodiments, only some contact portions of the coilcome in contact with the tubular braid, with other portions of the coilnot in contact with (spaced from) the braid. An example of this is shownin the cross-sectional view of FIG. 4F wherein the contact portions areonly at the proximal and distal end 27 a, 27 b. In other embodiments,more portions come into contact with the tubular braid. In someembodiments, since the tubular braid has peaks and valleys due tocrimping, the coil wire 27 comes into contact with some or all of theinner surface of the valleys and not in contact with the peaks. Anexample of this is shown in the cross-sectional view of FIG. 4G whereincoil 27 contacts the inward portions of the braid 12′.

8) One end of the tubular braid is heated to melt onto the coil toattach the tubular braid and coil (at a melt joint) to form thebraid/wire assembly (implant). The mandrel can be left during melting oralternatively removed prior to melting.

9) A filament (yarn or wire) is threaded through the device lumen (sothe device is able to slide over the filament) to aid in formation of asecond device configuration.

10) The filament (yarn or wire) is wound with the braid/coil assembly(device) on a mandrel or other fixture to a secondary helical shape andthen the assembly is heated to set in the secondary shape. In someembodiments, each successive heat treatment is at a higher temperatureand/or a longer duration to improve shape retention of that treatmentand to control shrinkage of the braid. By controlling previous heating,the final heat treatment can be used to impart the most shrinkage of thebraid to aid in setting the secondary shape. In the illustratedembodiment, the secondary shape is a helical shaped, although,alternatively, the secondary shape could be other 3D shapes, such asspherical, conical, etc.

11) The device (attached braid and coil) is removed from the oven tocool and the filament and shaping mandrel/fixture removed, leaving theassembly (implant) in its set secondary shape.

12) A nitinol tube such as tube 29 as discussed above (or alternativelya stainless steel tube) is inserted into the coil at one end of thetubular braid. The tube has a helical feature cut into one end. The tubein some embodiments is attached by rotating or screwing it in betweenthe windings of the coil wire so the helical feature interlocks with thewindings. Note that Nitinol provides resiliency which reduces thelikelihood to break when acting as a lock component with the pusher ofthe delivery system. Also Nitinol provides more favorable MRIvisualization (less interference). Note although the tube is preferablymade of Nitinol, alternatively other materials such as stainless steelcan be utilized. Preferably, the inner diameter and outer diameter ofthe tube is the same or substantially the same as the inner diameter andouter diameter of the coil wire so that the tube and coil wire aresubstantially flush. However, it is also contemplated, that the coil andtube can have a stepped surface.

13) In the next step, the braid is heated to melt onto the nitinol tubeand the end of the coil, thereby attaching the tube to the braid andcoil, forming the final assembly (micrograft/implant). Note that in someembodiments, the melted braid region covers the entire region where thehelical feature (thread) of the tube and coils of the metallic coil areintertwined. The material flowing into the helical structure reinforcesthe joint.

Crimping makes the tubular braid softer as there is more room for thetubular braid wall to compress. The increased compressibility enables ahigher packing density in the aneurysm, i.e., more implants can befitted in the aneurysm, and fill a higher volume. The increase in theamount of thrombogenic fiber per unit length of the device is alsodirectly proportional to the amount of crimping (compression) and asstated earlier, depending on the braid filament type or pattern, doesnot always result in peaks and valleys. It does, however, reduce braidcell size while increasing braid angle and outer diameter. As anexample, crimping a tubular braid by 50% (via axial compression) ineffect doubles the amount of fiber per unit length in the resultantstructure. This can be used to increase the amount of thrombogenicmaterial and surface area in a braided device as a secondary(post-braiding) step.

The sufficiently crimped braids (high braid angle) disclosed herein madewith multifilament yarns maintain a closed cell structure on the outerbend surface even if deflected or coiled in a secondary shape. That is,although the tubular braid in its coiled secondary shape will experiencecompression of the yarns/filaments on the inside of its bend radius andstretching/expansion of crimped yarns on the outside of the bend radius,it still does not allow visibility of the internal coil through thebraid surface. In other words, the crimped braid will maintain itsclosed cell configuration in the linear as well as in a non-linear,e.g., bent or curved or coiled, configuration. In contrast, foruncrimped and monofilament tubular braids, the inside bend surface willexperience compression and a reduction in cell size and porosity whereasthe outer bend surface will experience cell/pore size increase(resulting in open cell structure).

As can be appreciated, in the exemplary embodiment, the implant isformed into a secondary shape after insertion of a filament through thedevice lumen. Also, as can be appreciated, the inner coil is releasedfrom a tensioned positioned once inside the tubular braid to move to itsless tensioned more relaxed position. n this position, in someembodiments, portions of the coil may remain out of contact with thebraid.

By crimping the braid without the internal coil, avoidance ofcompression of the coil is achieved, which due to different heat settemperatures of the braid and coil materials, could result in the coilnot being shape set to a shorter length and remaining in tensionrelative to the braid. Also, since crimping increases the inner diameterof the braid, the inner diameter of the braid can be set and then a coilpositioned therein, which in some instances can have an outer diameterlarger than the internal diameter of the uncrimped braid. This enables alarger coil to be used. Note in an alternate method, the braid iscompressed with a coiled wire positioned inside, but the coiled wire isa closed pitch coil so it is not compressible. In this alternatemanufacturing method, the closed pitch coil is mechanically clamped to amandrel, so that when the braid is crimped, the coil cannot change inlength so therefore would not be under tension. Note that in eithermethod, compression of the braid is achieved without compression andtensioning of the inner coil wire. The former method utilizes an openpitch coil which facilitates healing. In yet another alternate method,the braided tubular structure is formed directly over the metallicmember whereby releasing the metallic member causes it to expand withinthe braid.

FIG. 3A illustrates another embodiment of an intra-aneurysmalmicrograft. A variable stiffness micrograft 26 with tubular body 28includes the same features and functions as described above with respectto FIG. 1 , or its alternatives, e.g., multifilament yarns, capillaryeffects, etc. However, in this embodiment, the micrograft 26, afterforming and crimping, is wound about a mandrel to form a secondary coilshape as shown. This is also shown in FIG. 16B wherein the micrograft 26is pictured both after braiding and crimping (still straight) and afterit is wound into a coil after formation of such braided and crimpedstructure. Such helical configuration is also shown in FIG. 4K where asecondary configuration of the micrograft 10′ of FIG. 4A is formed.Other micrografts described herein, with the varying features describedherein, can also be wound into a coil shape of FIG. 3A if desired. Thetubular body 28 of micrograft 26 is composed of a variable stiffnessbraid having a proximal stiff section 30 and a distal flexible section32, the varying stiffness achieved in the ways described above. Tubularbody 28 also has a primary diameter D. A radiopaque band 36 can beprovided to allow visualization under fluoroscopy and is shown in theapproximate center of the braid where it transitions in stiffness. Theradiopaque band 36 can alternatively be positioned in other locationsand multiple bands can be provided. Alternatively, radiopacity can beachieved in the various ways described above.

Device 26 is shape-set with heat in a pre-biased (secondary) helicalshape of FIG. 3A (and 16B). This is the delivered shape-set form of thedevice 26. This device may not have such pronounced peaks and valleys asmicrograft 10 due to the stretching, bending and heating needed to formsecondary shapes. However, the original crimping operation induces thedesired properties and makes the micrograft more compliant. Partialstretching or partial un-doing of the crimping also results in a braidedlumen that is more compliant radially for improved packing.

Although shown helically-shaped, device 26 can be shape set into anycomplex three dimensional configuration including, but not limited to, acloverleaf, a figure-8, a flower-shape, a vortex-shape, an ovoid,randomly shaped, or substantially spherical shape. As mentioned earlier,a soft, open pitch coil can be added to the inner diameter of the braidto aid in visualization. If stiffness of such metal coil is sufficientlylow, the secondary shape-set of the polymer braid will drive the overallshape of the device. In other words, the secondary shape of the braidmolds the unshaped metal coil which normally shape sets at temperaturesmuch greater than the glass transition temperature of polymers.

The micrograft 26 also has frayed end fibers 38 shown on one end of thedevice. These loose frayed fibers can alternatively be on both ends ofthe braid, if desired (other micrografts disclosed herein could alsohave such frayed ends). When these frayed ends come in contact withanother braid within the aneurysm sac having the same feature, themating ends act like Velcro, allowing the micrografts to interlock andmove together. For delivery and introduction into catheter, device 26would be elongated, e.g., moved to a substantially linear configuration,and inserted into a loading tube having an inner diameter of sufficientsize to accommodate primary diameter D. An optional filament (not shown)may extend from the proximal end of the braid to allowpinching/anchoring of the micrograft between a stent or flow diverterand the parent vessel wall upon release to obstruct flow at the aneurysmneck. Packaging and delivery is discussed in detail below.

FIG. 3B illustrates another embodiment of an intra-aneurysmalmicrograft. Sliced micrograft 40 has a tubular body 42 that can includethe same features and functions as described above for the previousembodiments, e.g., multifilament yarns, capillary effects, etc. Tubularbody 42 has a longitudinal cut 44 and is shape set to expose its innersurface 46, thereby providing a flared distal end. Micrograft 40 isconfigured with a portion of the inner diameter exposed to maximizesurface area constricted by flowing blood and to aid in movement withblood flow. Device 40 can include a proximal marker band 48 (oralternatively any of the other aforedescribed radiopaque features) forvisualization. Holes 50 and 52, formed by laser cut or other methods,provide for communication with the blood. Micrograft 40 is particularlysuited for placement at the neck of the aneurysm either manually with adelivery system or through movement with blood flow circulating withinthe aneurysm. Delivering micrografts 46 to an aneurysm may result inclogging at the neck/stent interface as they get caught up in exitingblood flow and accumulate at the aneurysm neck. This structure can alsobe a round tube, flattened tube, or other shape that is easily moved byblood flow.

The tubular bodies for the above embodiments have been described ascrimped braided tubes, however, the tubes can be made using othermanufacturing methods such as weaving, knitting, extruding, orelectro-spinning. Structures can also be manufactured with alternatingdiameters or cross-sections, such as flat to round. In addition, thetube can be made from a rolled sheet or other material formed intodesired tubular or substantially cylindrical structures. Structuralflexibility can then be adjusted either by crimping or selective lasercutting, for example. If desired, the tubular body can also be flattenedto create a thin walled tape or heat pressed to create oval sections.

Also, although crimping, or the use of axial/longitudinal compressionand heat is described to produce crimps or peaks and valleys, othermanufacturing methods of constructing peaks and valleys can be utilizedto achieve similar effects. For example, a wire may be wound tightlyaround a braid placed on a mandrel. The gaps between windings willcreate peaks and when the assembly is heat set (with or withoutlongitudinal compression) and the wire removed, valleys will be formedwhere the wire compressed the braid and peaks where the braid wasexposed.

FIGS. 16A through 16C and FIG. 17 illustrate a portion of micrograft 10tubular body 12 constructed of 20 denier/18 filament polyester yarn.FIG. 16A shows examples of an uncrimped tubular body 171 alongside acrimped micrograft 10 tubular body 12 to illustrate the formed macropeaks and valleys. FIG. 16B shows a crimped tubular body alongside atubular body that has been shape set into a helical coil 172 postcrimping similar to FIG. 3A. FIG. 16C shows micrograft 10 that has fluid174 which has been drawn into the micrograft via capillary actiondescribed earlier. FIG. 17 shows a tubular body with a marker band (stopcollar) 22 attached to the body as in FIG. 1 .

Turning now the delivery of the micrografts, several embodiments ofdelivery systems of the present invention are disclosed. Many of thedelivery systems enable over the wire insertion which minimizesmicrograft snaking inside the catheter as well as enables delivery oflonger length micrografts. The delivery systems also enableretrievability of the micrograft after partial deployment, and in someembodiments, even after full deployment.

Turning to a first embodiment and with reference to FIGS. 5A-5D, anintra-aneurysmal micrograft delivery system is illustrated anddesignated generally by reference number 54. The delivery system isdescribed below for delivering micrograft but it should be understoodthat it (as well as the other delivery systems described herein) can beused to deliver any of the micrografts disclosed herein. Delivery system54 includes a pre-loaded delivery wire 62 for carrying the micrograftand a pusher catheter 58, the pre-loaded delivery wire 62 positionedwithin the pusher catheter 58. Optionally the system could include aloading sheath similar to the loading sheath of FIG. 7 described belowwhich is positioned thereover to retain the micrograft on the deliverywire 62. The individual components of the delivery system can be removedfrom the packaging during the procedure and assembled by inserting thedelivery wire 62 proximally through the catheter 58 creating a junction57 at the proximal end of the micrograft 10 and the distal end of thepusher catheter 58. Alternatively, they can be pre-packaged with thedelivery wire 62 already positioned within the pusher catheter 58 and aprotective loading sheath similar to the loading sheath of FIG. 7positioned thereover to retain the micrograft 10 on the delivery wire62. This delivery system may be used as a standalone delivery system toaccess the target anatomy, or with a microcatheter as described below.Any necessary flushing or coating activation can be done per physician'sdiscretion prior to insertion into the patient.

Delivery wire 62 has micrograft 10 mounted thereon at region 56.Delivery wire 62 has a body with a length extending from proximal end 64to distal end 66 can range between about 20 cm and about 400 cm, andmore particularly between about 100 cm and about 300 cm, and even moreparticularly about 200 cm. Suitable diameters for the delivery wire 62can range from about 0.0025 inches to about 0.040 inches, and morenarrowly between about 0.002 inches and about 0.035 inches. The overalldiameter of the delivery wire may be continuous, for example about0.014″ or the wire may taper from proximal to distal direction, forexample about 0.007 inches to about 0.003 inches. Other sizes are alsocontemplated, dependent on the pusher catheter and/or microcatheter IDused for the procedure.

The distal portion 68 of the delivery wire 62 can include a coil and thevery distal tip 66 of delivery wire 62 can be bulbous, of increaseddiameter, or fitted with a marker band or coil. The distal portion 68 ofthe delivery wire may be radiopaque as well as able to be shape set toaid in tracking, vessel selection, and intra-aneurysm maneuvering. Forexample the distal portion can be shape set to J-shape as in FIG. 11Adescribed below. The delivery wire 62 may also be coated with ahydrophilic coating. The delivery wire 62 includes a retaining structuresuch as a tapered region to aid in retention of the micrograft thereon.In alternative embodiments, to further aid retention, or if a deliverywire is utilized which does not have such retention structure such as astandard guidewire, then a protective loading sheath can be utilized. Inanother embodiment, the micrograft can be mounted using the micrograftintroducer system 136 as described below with regard to FIG. 9 .

Delivery wire 62 has a tapered region 70 (FIG. 5C) forming an engagementstructure for mounting the micrograft 10. A proximal stop collar 22 ispositioned over the tapered region 70. The stop collar 22 can beattached to the delivery wire 62 or alternatively and preferably form aretaining feature attached to an internal portion of the micrograft 10.In either case, the proximal end of the micrograft 10 is frictionallyengaged and retained by the delivery wire 62. Micrograft 10 is mountedcoaxially (and slidably) on wire 62 a distance L from the wire distaltip 66. The distance L is set by the proximal stop collar 22 whichinteracts with wire taper 70 as shown in FIG. 5C, or other hard stop onthe wire (e.g., a marker band), and the overall length of themicrograft. For instance, longer micrografts may have a small distanceL. In some embodiments, distance L may be zero and the hard stop may beon, inside or near the distal end of the micrograft 10 to interact witha bump, bulb or head (such has a head 184 of FIG. 5E described below) onthe distal end of the delivery wire 62 to prevent the delivery wire 62from passing through the distal end of the graft. In this instance, thedistal tip of the micrograft 10 would be adjacent the distal end of thedelivery wire 62 as in the embodiment of FIG. 5E.

FIG. 5C shows an enlarged cross sectional view of the proximal end ofmicrograft 10 with stop collar 22 engaging tapered region 70 of thedelivery wire 62. The stop collar 22 as shown is in the form of a markerband to provide radiopacity for visualization. The wire taper 70 acts asa proximal stop to prohibit proximal movement of the micrograft 10 overthe wire 62.

Other ways to couple or mate the micrograft and the delivery wire 62 arealso contemplated. As mentioned earlier, proximal and distal Nitinolparts may be added to the micrograft as stops, or other parts and/orfeatures (e.g., platinum marker band, notch, bump, etc.) can be added tothe delivery wire to act as stops. In some instances, there may be nostop collar, the stop may be on the distal end of the braid (asmentioned above), the pusher catheter may act as the proximal stop, orthe micrograft 10 can be sized to be free to slide across the entirelength of the delivery wire, proximal to distal.

The pre-loaded delivery wire 62 may be supplied with one or moremicrografts covered by a protective cover such as cover 92 of FIG. 7 .This cover 92 has a tapered tip tapering to a smaller outer dimensionfor introduction into the lumen of a microcatheter or component thereof.

In some embodiments, more than one micrograft can be loaded on thedelivery wire. They can be linked together on the delivery wire fordelivery using one of the frayed, Velcro-like ends 38 described abovewith respect to FIG. 3 or inter-connected with assistance of the coaxialdelivery wire running through them. That is, the device can in someembodiments be supplied pre-packaged with a plurality of micrografts inline along the delivery wire.

As mentioned above, the delivery system 54 includes a pusher catheter 58having a lumen through which the delivery wire 62 extends. Pushercatheter 58 includes a catheter body 72 and a Luer lock 74. Catheterbody 72 is preferably of a variable stiffness construction with a stiffproximal section, softer mid-section and still softer distal section.Individual sections of the catheter may be made up of polymer tubingwith varying durometers to control stiffness, proximal to distal. Thebody may also be made from a variable stiffness, laser cut tube made ofstainless steel alloy or Nitinol, for example. If polymer tubes areused, the catheter may also be a braid or a coil reinforced to keep fromovalizing. A lubricous liner made from materials such as PTFE, ePTFE, orFEP may also be added to the structure.

The outer diameter of the pusher catheter 58 is dimensioned to slidefreely inside microcatheters with inner diameters ranging from about0.008 inches to about 0.070 inches. Catheter body 72 can include ahydrophilic coating on its outer diameter for lubricity. The length ofthe catheter body 72 is preferably slightly shorter than the deliverywire 62 to allow proximal access to the delivery wire 62, i.e., holdingthe wire 62, while a micrograft (or multiple micrografts) is loaded onthe distal end. The inner diameter of pusher catheter body 72 or thedistal end is sized and shaped so that the micrograft 10 cannot beforced inside the catheter body 72 during distal advancement or proximalpulling of delivery wire 62. When loaded in the pusher catheter 58, thedelivery wire 62 is preferably free to rotate and to move in a linear(back and forth) motion relative to the pusher catheter 58.Additionally, the pusher catheter 58 can be designed to accommodatedelivery of stents or other devices or fluids to the target anatomy. Insome embodiments, a clearance between an outer dimension of the deliverymember and an inner dimension of the occluding device is substantiallyfluid-tight before delivery into the aneurysm but sufficient to enableslidable movement of the delivery member with respect to the occludingdevice.

At or near the distal end of pusher catheter body 72 is radiopaquemarker band 76 which can be made of platinum/iridium and attached withadhesive, heat shrink tubing, a swaging process, or other known methods.Alternatively, the marker band can be placed inside the pusher catheter58 with the delivery wire 62 passing through it. Other suitableradiopaque materials for marker band 76 include gold, silver, andradiopaque shrink tubes, or metal coils for example. A luer lock 74 canbe positioned at the proximal end of the catheter 58 and attached to theluer lock 74 is a rotating hemostatic valve (RHV) 78 for saline, drug,contrast media or other fluid introduction though the inner diameter ofpusher catheter 58. The RHV 78 also serves as a lock to stop relativemovement between the pusher catheter 58 and the pre-loaded delivery wire62 when the RHV 78 is tightened over (clamped onto) the wire. In someembodiments, the pusher catheter 58 can be delivered pre-packaged andsterile with an RHV as an accessory. In embodiments where a co-axialcatheter stent delivery system is used, a pusher catheter may not berequired as after stent deployment by the stent delivery catheter, themicrograft loaded delivery wire can be inserted into the stent deliverycatheter to deploy micrografts.

As described earlier, the delivery wire 62 may be used as the primaryaccess wire as in conventional guidewires. FIG. 6 illustrates analternate design to the over-the wire pusher catheter, which is a rapidexchange pusher catheter designated generally by the reference number80. The rapid exchange (RX) pusher catheter 80 has a catheter body 82with marker band 76 at a distal end and a stiff push wire 84. Catheterbody 82 will share many of the same features as the mid and distalsection of catheter body 72 described above, including coating. Thestiff pusher wire 84, which may taper, can be made of stainless steelalloy, Nitinol, or other suitable material. The pusher wire 84 mayalternately be a hypo-tube, with or without laser cutting, or a wirefeaturing a non-round cross-section. The device may be suppliedpre-packaged and sterile. In use, the RX catheter may be inserted overthe delivery wire or guide wire before or after the aneurysm is accessedby the wire.

FIG. 5E-5G illustrate a delivery system 180 for delivering themicrograft 10′ of FIG. 4A. The delivery system has a pusher member 186and delivery wire 182 with an enlarged head 184. In the initial positionof FIG. 5E the tab 29 a of micrograft 10′ is bent downwardly and thedelivery wire 182 passes through window 29 b. The delivery wire 182extends within micrograft 10′ to the distal end of the micrograft 10′.In this position, head 184 engages the proximal edge of stop 22, e.g.,distal marker band 22, on micrograft 10′.

The pusher member or catheter 186 has an internal stop 188 at its distalend to aid with pushing micrograft 10′ as well as to inhibit movement ofmicrograft 10′ into the pusher member's inner diameter. The pushercatheter 186 is shown by way of example without a luer attachment. Boththe pusher catheter 186 and the delivery wire 182 may be constructed aspreviously described. In addition, although not shown, system 180 caninclude a protective introducer sheath similar to the loading sheath 92of FIG. 7 to limit micrograft movement as well as to assist inmicrograft introduction into a microcatheter.

In the initial position, tab 29 a of micrograft 10′ is bent downwardlyand the delivery wire 182 passes through window 29 b (FIG. 5E). Thedelivery wire 182, as mentioned above, extends inside the graft 10′ suchthat enlarged head 184 comes into contact with the proximal edge of stop22. Note, although the stop 22 is shown as open, it may be completelyclosed. Also, the stop may be excluded and the braid may be melted tonarrow or close the distal end of the braid to prohibit the wire 182from exiting. The use of a distal stop also serves the purpose ofkeeping the micrograft 10′ in tension which aids in delivery bystretching and reducing the outer diameter of the micrograft 10′.

The tab 29 a provides a force against the delivery wire 182 to retainthe micrograft on the wire 182. Upon delivery, the wire 182 is retractedto the position of FIG. 5F where delivery wire enlarged tip 184 engagesthe tab 29 a. Up to this position the micrograft 10′ can be retrievedfrom the aneurysm and/or maneuvered therein. Next, pusher catheter 186is advanced (or wire tip retracted) to force the tab 29 a to theposition of FIG. 5G, therefore enabling full retraction of the enlargedhead 184 of the delivery wire 182 through window 29 b for release of themicrograft 10′ from the delivery wire 182. FIG. 5H shows the tab 29 areturned to its original position longitudinally aligned with themicrograft 10′ after retraction of the delivery system.

FIG. 7 illustrates another embodiment of an intra-aneurysmal micrograftdelivery system generally referred to by reference number 86. Deliverysystem 86 comprises a pusher wire 88 and a loading tube 92. Pusher wire88 includes an elongate tapering flexible wire that can be made fromstainless steel, or alternatively, Nitinol, plastic or other inert orbiocompatible material or combination thereof. Although shown as a wire,the pusher wire can alternatively be a hypo-tube with a Luer lock.

At the distal end of pusher wire 88 are expanding grasper members orarms 94, 98. Although there are four grasper arms in this design, moreor less than four arms may be used. The arms 94, 98 can be made of shapeset shape memory material such as Nitinol, spring tempered stainlesssteel, radiopaque metal, or other suitable material. The arms 94, 98 canalternatively be manufactured from a metal or elastic tube which islaser cut to create deflectable arms. Attached to the distal end of oneor more of the grasper arms are radiopaque bands (see labeled bands 102,106, and 108; the fourth band not shown since the fourth arm is notshown). The bands can be attached with glue, solder or other methods.The proximal ends of the arms are attached to the pusher wire 88 by acoil 110 which can be made of wound stainless steel or platinum iridium,for example. Attachment methods may include gluing, welding, orsoldering. The use of the grasping arms has the advantage of enablinggrasping of the micrograft after full deployment to retrieve/remove themicrograft or to maneuver/reposition the micrograft within the aneurysmas described below.

The pusher wire 88 has a length (including arms) between about 20 cm andabout 400 cm, more narrowly between about 100 cm and about 300 cm, forexample about 200 cm. Suitable diameters for the pusher wire 88 canrange from about 0.006 inches to about 0.040 inches, more narrowlybetween about 0.008 inches and about 0.035 inches. The overall diameterof the pusher wire 88 may taper from proximal to distal, for exampleabout 0.014 inches tapering to about 0.003 inches. The pusher wire 88,either in part or whole, may be coated with a hydrophilic or PTFEcoating for lubricity.

Loading tube 92 is made of either metal or plastic and preferably hasdistal taper 112 for mating with a microcatheter Luer taper. The loadingtube 92 preferably has a length sufficient to cover the entiremicrograft 90 and at least a portion of coil 110. The inner diameter ofthe loading tube 92 is preferably close to the inner diameter of themicrocatheter to which it will mate. A range for the inner diameter maybe between about inches and about 0.070 inches. The loading tube mayhave a crimp or other fixation method to prevent relative movement tothe pusher wire 88. If used on a structure having a Luer or otherattachment on its proximal end, the introducer may have a lengthwiseslit to aid in removal (i.e., peel-away).

One way to load micrograft 90, which has proximal band 114, e.g., amarker band, is to position the loading tube 92 on pusher wire 88 justproximal to the two pair of grasper arms 94, 98 so that the arms are intheir normal expanded position. The band 114 on micrograft 90 is thenpositioned between bands 102 and 104 (one on each arm of arms 94) andbands 106 and 108 of arms 98. Note to achieve axially spaced bands, thearms 94 can be shorter than arms 98 so the bands 102, 104 are proximalof bands 106, 108, or alternatively, the arms 94, 98 can be the samesize and bands 102, 104 can be placed on a more proximal position ofarms 94 (spaced from the distal end) while bands 106, 108 can be placedon a distal end or more distal position of arms 98. The loading tube 92is then advanced forward (distally) compressing the pusher arms 94, 98to a collapsed or compressed position to engage (grasp) the band 114 toretain the micrograft 90 in place. Thus, band 114 forms an engaging orretention structure for engagement by the pusher (delivery) wire 88 toretain the micrograft 90 on the wire 88.

Note micrograft 90 is similar to micrograft 10 except for the proximalband 114 which is positioned around a portion of the braided structure.

Note alternatively, instead of the micrograft having a single proximalmarker band, it may have two proximal bands where the bands of thepusher wire sit to create a lock when compressed inside the lumen of theloading tube. Alternatively, a micrograft with an internal coil may haveproximal coil windings spaced to have a gap that allows radialcompression and grasping by the bands of the pusher wire.

FIG. 8 illustrates yet another embodiment of an intra-aneurysmalmicrograft delivery system generally referred to by reference number116. Delivery system 116 is a neurovascular stent-graft kit thatcomprises a pusher wire 118 with distal band 120, stent or flow diverter122 with proximal arms with bands 124 and 126 and distal arms with bands128 and 130, micrograft 132 with proximal band 134, and loading tube133. The micrograft 132 is locked proximally by the stent 122 and stentbands 128 and 130 and loading tube 133. Stent or flow diverter 122 is inturn locked to pusher wire 118 using a similar locking concept as bands124, 126 are blocked by band 120. The number of arms for both lockingsystems may vary to be more or less than two. Delivery system 116 canalso be configured to have a through lumen for guidewire delivery.

The delivery system 116 provides a single delivery system that candeliver a micrograft and a stent that can be combined on site to form aneurovascular stent-graft. Alternately, the stent may be permanentlyattached to the pusher wire and acts as a temporary stent to push graftsinto the aneurysm.

FIG. 9 illustrates a micrograft introducer system 136 which may be usedto mount micrografts on a delivery wire or on a guidewire before orduring a medical procedure. Micrograft loader introducer system 136comprises introducer sheath 138 loaded with micrograft 10. Theintroducer sheath includes tubular body 140, Luer lock 142, and stoptube 144. Tubular body 140 can be made of metal, plastic or acombination of materials and sized with an inner diameter between about0.008 inches and about inches and a length that covers all orsubstantially all of the micrograft 10. The distal tip of the tubularbody 140 may be straight or tapered to help in micrograft introductionand handling. The Luer lock can be attached to an RHV such as RHV 78 ofFIG. 5D for the introduction of fluid such as, saline or contrast media,guide or delivery wires and pusher catheters. The stop tube 144, whichis optional, has a through lumen and can be made of plastic or metal andmay have a taper proximal to distal. The purpose of the stop tube is toprohibit the micrograft from exiting the tubular body 140 prior toloading and may be removed prior to insertion.

Although FIG. 9 shows only one micrograft, multiple micrografts may bedelivered in a single introducer sheath. They may be free to moverelative to one another or linked together using the frayed ends method,for example, as described above. Micrografts having secondary shapeswill generally be linear or straight when loaded into the introducersheath such that they are concentric.

Introducer system 136 is delivered pre-packaged and sterilized. Onceopened, an RHV and syringe may be attached to the Luer to introducefluids. A delivery wire or guidewire may be pushed into the introducersheath 138 to mount the micrograft(s) on the wire or alternatively theintroducer sheath 138 may be mated with the proximal end of themicrocatheter and the micrografts may be pushed proximally through thesheath 138 and into the microcatheter using a pusher catheter, with orwithout a wire, or with a commercially available pusher wire.

The micrografts disclosed herein can be preset to a non-linearconfiguration and advanced to the aneurysm in a substantially linearconfiguration and then return to the same non-linear configuration ordifferent non-linear configuration when delivered into the aneurysm,depending on the space within the aneurysm.

FIGS. 10 through 11F show the preferred method of using intra-aneurysmalmicrograft delivery system 54 of FIG. 5A to deploy micrograft 10 of FIG.1 . (Other micrografts described herein can be inserted in a similarfashion). The micrograft delivery method, as well as the “viscositylock” function (described below) are depicted in flow chart form inFIGS. 18 and 19 . Before implantation, the delivery system may beprepared prior to patient insertion as described above or as preferredby the physician.

Typical intracranial aneurysm access requires inserting a guide catheterinto the femoral artery and then tracking a microcatheter in combinationwith a primary guidewire through the vasculature until the aneurysm siteis reached. Once there, the primary guidewire is removed and replacedwith an embolization system. FIG. 10 shows micrograft delivery system 54of FIG. 5A being inserted as a unit into the proximal end ofmicrocatheter 146 (with attached RHV 148), the microcatheter 146 havingbeen inserted through the guide catheter and advanced to the aneurysmsite and the primary guidewire removed.

FIG. 11A illustrates the distal tip 66 of delivery wire 62 exitingmicrocatheter 146 that has been positioned inside aneurysm 150 and isheld in place using a “jailing” stenting technique, surrounded by blood152. Jailing refers to the use of a stent or flow diverter 154 to pinthe distal tip of the microcatheter between the parent vessel intima andthe stent or flow diverter 154, so that the microcatheter tip is heldwithin the aneurysm and delivered occluding devices, e.g., micrografts10, are kept out of the parent vessel lumen. Other techniques that maybe used instead of jailing include temporary stenting and balloonremodeling. It is also contemplated that the micrografts of the presentinvention be deployed without the use of such parent vessel support(stent or flow diverter) devices.

Once the system is in place as shown in FIG. 11A, the exposed deliverywire tip 66, which has the pre-bent curve as shown, is slowly retractedinto the micrograft 10. The retraction can be done in incremental stepsof a few centimeters or completely until it reaches a location at, ornear, the pusher/micrograft juncture 57 (see FIG. 5A). As the deliverywire 62 is retracted proximally toward junction 57, blood 152 will bedrawn into the micrograft's inner lumen to fill the volume previouslyoccupied by the delivery wire 62, as depicted in FIGS. 11B and 11C. Thisfilling action occurs through a combination of the unique internalcapillary features of the micrograft described earlier and due to asyringe-like “piston” effect of the receding wire.

With the delivery wire 62 pulled back and in some embodiments pulledback to a locked position against tab 21 a, as in the embodiment of FIG.5F, the micrograft 10 can be pushed forward off the wire 62 and into theaneurysm as illustrated in FIG. 11D using the pusher catheter 58 (FIG.5A) as it is advanced distally and engages the proximal end of themicrograft 10. Note that if the delivery system does not feature amechanical lock physically connecting the pusher catheter 58 or deliverywire 62 to the micrograft 10, the micrograft 10 may still be retrieveddue to a “viscosity lock” (described below) that is formed inside themicrocatheter 146, between the delivery system components andmicrograft, once surrounded by a viscous liquid (e.g., blood). This lockallows the micrograft 10 to be advanced and retracted while the proximalend of the micrograft 10 remains inside the lumen of the microcatheter146 until desired placement is achieved.

Micrograft 10 is pushed forward by pusher catheter 58 and the wire 62can be pulled further proximally to junction 57, if it is not positionedthere already. Once the wire 62 reaches junction 57, the inner lumen ofthe micrograft 10 will be completely filled with blood 152 thatdisplaces the wire 62 and with any liquid that has been present (e.g.,contrast). Since blood now fills the inside lumen of the micrograft 10and has already permeated the braided walls via the aforedescribedcapillary action, the saturated device is composed in part of thepatient's blood. Thrombosis and cell in-growth through the microporousyarns will be accelerated as the blood becomes trapped and stagnantwithin the micrograft (implant) after delivery.

Note that blood can enter the lumen of the micrograft 10 through adistal opening of the lumen and/or through other intermediate orproximal regions of the lumen spaced from the distal end as blood isabsorbed through the braided structure. As blood enters suchintermediate or proximal regions, it spreads in various dimensions aswell as is directed proximally due to the aforedescribed capillaryaction.

As the micrograft 10 is deployed into the aneurysm, it will take on anypreset secondary shapes and random shapes due to contact with aneurysmwalls or the stent/flow diverter 154, as shown in FIGS. 11D and 11E.That is, in these Figures, micrograft 10 has a pre-set U-shape as shown,however, this shape can change as it contacts the aneurysm wall and/orstent 154. If the proximal end of micrograft 10 remains inside themicrocatheter, the micrograft 10 can be retracted and repositioned atany time prior to full deployment as described above. The micrograft 10will be fully deployed and disengage from the delivery system once thedistal tip of the pusher catheter 58 reaches or exits the distal end ofthe microcatheter 146. FIG. 11E shows an enlarged cross section of thefully deployed pre-shaped blood filled micrograft 10 of FIG. 11D.

After the first micrograft 10 has been deployed, the delivery wire 62and pusher catheter 58 are removed and, if needed, another micrograft 10is loaded on the wire 62 or a new delivery system is opened, and thedeployment process is repeated as described above. Multiple micrograftscan be deployed by repeating the above steps until the aneurysm issufficiently packed (per physician discretion) as shown in FIG. 11F. Ifneeded, the microcatheter tip or the delivery wire 62 can be used inbetween packing or during packing to move or compress micrografts withinthe aneurysm. Once the aneurysm is sufficiently packed, themicrocatheter is removed and the stent or flow diverter 154 continues toexpand to cover the neck of the aneurysm 158 to thereby block exit ofthe micrografts 10 from the aneurysm sac. Together, micrograft 10 andstent or flow diverter 154 form neurovascular stent-graft 160, as shownin FIG. 11F.

As mentioned above, delivery system 54 features a temporary liquid sealor “viscosity lock” effect inside the microcatheter which allows limitedretrieveability (push/pull) of the micrograft during placement. The“pull” of the lock is generated by the tip of the pusher catheter 58,which creates a syringe-like “piston” within the fluid-filledmicrocatheter 146. Functionality of this lock is dependent on clearancesbetween the microcatheter lumen, proximal micrograft 10 body, adjacentpusher 58 tip, the delivery wire 62, as well as the viscous and cohesiveproperties of the fluid medium.

The flow chart of FIG. 19 describes the steps of the viscosity lockfunction which are as follows:

1) Inside the aneurysm, align tip of delivery wire 62 with distal end ofmicrograft 10.

2) Retract wire 62 to draw blood inside micrograft lumen up to thepusher junction 57.

3) Push delivery system (pusher 58+wire 62) to advance micrograft 10 outof catheter 146.

4) While maintaining proximal end of micrograft 10 inside catheter 146,pull on delivery system to retract micrograft 10.

5) Re-deploy micrograft 10 once re-positioned by pushing on deliverysystem.

6) Release blood filled micrograft 10 by pushing proximal end ofmicrograft 10 out of catheter 146.

7) Repeat process to deliver another micrograft 10, or remove deliverysystem and load additional micrograft 10 onto distal wire tip.

In order for the viscosity lock to work, viscous liquid (i.e., blood)must fill the microcatheter past the micrograft/pusher junction. Onceviscous fluid fills the micrograft(s) 10 and gaps around the pusherjunction 57, it acts as a “gasket”, or a seal, around thepusher/micrograft junction 57 during any displacement (i.e., as thepusher is retracted). The action of pulling the pusher 58 (i.e., thepiston) adjacent to the proximal end of the micrograft now creates a lowpressure volume. This causes the micrograft(s) 10 suspended in blood toget suctioned and retract within the microcatheter 146.

The micrograft 10 may also be retractable if the delivery wire distaltip 66 is pulled back proximal to the distal tip of pusher 58 or removedcompletely. High friction or pull resistance is more likely to break the“viscous lock”, so the preferred application for this retrieval methodis with shorter, lower friction devices or where minimal tortuosity andresistive forces are involved.

In some embodiments of the micrograft delivery system, a pusher wire ordelivery wire may not be present inside the micrograft lumen andinternal filling of the micrograft with blood will be induced bypressure from the patient's circulatory system or via capillary forces.Capillarity can be achieved by the micrograft having appropriately sizedinner diameter or pores, as described earlier. Hence, the absorption ofblood into micrograft depicted in FIG. 11C can occur upon contact withblood even if delivery wire or external force is not used to draw bloodin.

FIG. 20A-24 illustrate alternate embodiments of the delivery systems ofthe present invention having alternate locking systems which include acompression coil to apply a distally directed force on the micrograft tofacilitate advancement to the target site. The coil is compressed by themicrograft when loaded in the delivery catheter and when the engagingmember is released from engagement with the micrograft, the springreturns to its normal state to exert a force on the micrograft.Micrograft 100, identical to micrograft 10′ of FIG. 4 , except withoutthe deflectable tab 29 a, is shown in the delivery systems of FIGS.21A-22C, 23B, and 24 , however, it should be understood, that thedelivery systems of FIGS. 20A-24 can be utilized to delivery othermicrografts disclosed herein, as well as other micrograft structures orother implantable devices.

Turning first to the embodiment of FIG. 20A, this version does notinclude a pusher wire or delivery wire within the micrograft lumen,relying on the micrograft configuration to achieve capillarity asmentioned above. The locking system of Figure is designated generally byreference numeral 190 and includes a compression coil 192 with a distalend 194, an elongated member in the form of a wire or ribbon 196 with alocking/engaging member in the form of a ball 198 at a distal portion,and a marker band 200. A hood 202 can be provided overlying the lockingball 198 and a portion of the lock wire 196 and coil 192. The lockingball 198 is configured to releasably engage the micrograft as describedbelow.

Compression coil 192 can be made of spring tempered stainless steel,Nitinol, polymers or any other material suitable for manufacturingcompression coils, including radiopaque materials such asplatinum/iridium. The compression coil in some embodiments has a lengthbetween about 2 mm and about 5 cm, more narrowly between about 3 mm andabout 2 cm, for example about 5 mm. Suitable diameters for thecompression coil 192 in some embodiments can range from about 0.006inches to about inches, more narrowly between about 0.010 inches andabout 0.018 inches. Other lengths and diameters are also contemplated.The coil can be open or closed pitch and can have optionally square orground ends which optionally can be welded, e.g. laser welded.

At the distal end 194 of the coil 192 a hood 202 can be provided whichextends over the top of locking ball 198. Hood 202 can be made ofplastic or metal, but preferably the hood is made of plastic. Itillustratively extends over the first 2 to 3 distal windings of coil192, but can be made of different lengths to extend over a differentnumber of coils. The hood 202 is secured to coil 192 by various methodssuch as melting it into the coil windings using a hot air source andremovable shrink tube or other methods such as over molding. The hood202 can extend distally beyond coil 192 and be cut at an angle (asshown), square, or flush with the coil depending on the matingcomponent. The hood 202 limits vertical motion (i.e., transversemovement with respect to a longitudinal axis of the ball lock wire 196)of the locking ball 198 and keeps it from disengaging from themicrograft during tracking of the system through the vasculature to thetarget site. The hood 202 can have a smooth outer surface to reducefriction inside the catheter. An alternative way to control vertical(transverse) movement of the locking ball 198 is to add material (suchas glue or solder) to the top surface of lock wire 196 or locking ball198.

The ball lock wire 196 with locking ball 198 can be made of materialwith a flat, round, or varying cross-section with one end of thematerial melted or formed to create the ball or enlarged feature. Thelock wire material can be spring tempered stainless steel, Nitinol,polymer or any other material suitable for manufacturing ball-end wires,including radiopaque materials such as platinum/tungsten. The ball lockwire 196 can in some embodiments have a length equal to or longer thanthe length of the compression coil 192. The locking ball 198 at the endof the wire can in some embodiments have a diameter in the range ofabout 0.004 inches to about 0.040 inches, and more narrowly in a rangeof about 0.006 inches to about 0.012 inches. The locking ball 198 can becentered or offset relative to the longitudinal axis of the wire 196,depending on the structure it is intended to mate with. In theembodiment of FIG. 20A it is shown offset.

The locking system sub-assembly of FIG. 20A can be assembled byinserting the ball lock wire 196 into the compression coil 192 andaligning it so that the locking ball 198 is covered by the hood 202. Thelocking ball 198 can be positioned inside the compression coil 192 or adistance away from the distal end 194 of coil 192 depending on desiredcoil compression (release force). The larger portion of the ball 198 (ifoffset) preferably faces down or away from the hood 202. An optionalmarker band 200 is partially or completely inserted into the proximalend of coil 192, pinning the wire 196 between the band 200 and the coil192. The mated components are then soldered or glued to form a joint atthe proximal end of compression coil 192 resulting in the locking systemsub-assembly 190.

The locking system sub-assembly 190 can be attached to a pusher wire 188(FIG. 20A) similar to pusher wire 88 described in the embodiment of FIG.7 above except without the grasper arm. The pusher wire 188 can be solidif desired since a delivery wire need not be utilized. Alternatively,the locking system sub-assembly 190 can be attached to a pusher memberor catheter such as pusher 189 of FIG. 20B similar to pusher member 186described in the embodiment of FIG. 5E above. In this embodiment of FIG.20B, the pusher member 189 has a lumen extending therethrough forreceiving a delivery wire.

In assembly of the delivery system of FIG. 20A the distal end of thepusher wire 188 is slid through the marker band 200, which is positionedinside, and can extend partially outside (proximal) of proximal end ofthe coil 192, and soldered or glued in place to the marker band 200.Thus, if the marker band 200 is used, the locking wire 196 is directlyattached to the marker band 200 (and coil 192). If a marker band is notused, the locking wire 196 can be directly soldered or otherwiseattached to the pusher wire 188 (and coil 192). Also, a shrink tube (notshown) can be melted over the proximal end of the joint to smooth outany edges and improve tracking around bends. Alternatively, the pushwire 188 can be flattened or round at its distal end and a locking ballsuch as locking ball 198 can be formed on its tip, which would eliminatethe need for ball lock wire 196. The locking system components can alsobe attached to the pusher wire individually and not as a sub-assembly asdescribed above.

In the embodiment where the locking assembly 190 is attached to a pushermember (pusher tube) such as the pusher member 189 shown in FIG. 20B,the marker band 200 can have an open lumen to accept delivery wire 182therethrough which also extends through a lumen in the pusher member189. The band 200 extends slightly proximally from the proximal end ofcoil 192 so that it can be inserted into pusher member 189 for assembly.Optionally, a shrink tube (not shown) can be melted over the proximalend of the joint to cover any edges and improve tracking around bends.The locking system components can also be attached to the pusher memberindividually and not as a sub-assembly as described above.

Note FIG. 20B shows an alternate locking mechanism attached to pushertube 189, but, as noted above, the locking mechanism 190 of FIG. 20A canbe used with the pusher tube 189. In the embodiment of FIG. 20B, insteadof a locking ball, the locking wire or ribbon (elongated member) oflocking mechanism 191 has a flat wire form 204 bent transversely(downwardly as viewed in the orientation of FIG. 20B) with respect tothe longitudinal axis. This forms a V-shaped hook like structure toengage the micrograft. Note this embodiment is shown in use with adelivery wire 182 such as the delivery wire 182 of FIGS. 5A-5E, whichhas an enlarged head 183. Like the embodiment of FIG. 20A, the lockingsubassembly includes a compression coil 192 positioned over the wire (orribbon) 204 and marker band 200, with the longitudinally extendingportion of wire 204 pinned between the coil 192 and marker band 200.

The locking wire and locking ball may be formed from a single laser cuttube 218, as shown in the embodiment of FIGS. 22A-22C, which extendswithin, e.g., is concentric with, compression coil 192, the pushermember (e.g., pusher member 189 (not shown)), and tube 129′ of themicrograft 100 to aid in assembly and delivery. This is achieved bylaser cutting a long thin section of tubing wall to make a locking wire214 that transitions on the proximal end from a tube 218, while a distalend of the long thin section is melted into a lock ball 216. Laser cuttube 218 material is Nitinol, but it can be any other shape memorymaterial, metal or polymer, or other materials, with sufficientflexibility and tensile strength. Alternatively, instead of being formedmonolithically, the locking ball may be formed by joining or melting aradiopaque material to the end of locking wire, such as soldering aplatinum/iridium marker band to the distal tip of locking wire. In theembodiment of FIGS. 22A-22C, the locking ball 216 is shown in engagementwith a cutout in the tube 129′ of the micrograft. Note as in theembodiment of FIG. 22A, a compression coil 192 is assembled concentricwith the wire 214 that is laser cut from tube 218. Note the tube 218 canbe radiopaque to also function as a marker.

FIGS. 21A and 21B show locking sub-assembly 190 of FIG. 20A without theuse of the hood 202 and with the use of a delivery wire 182. The lockingassembly 190 is fitted to a pusher member 189 and shown locked to themicrograft 100 by way of example. The locking assembly 190 is showninside introducer sheath 208 (shown in cross section). Core element 101(identical to core element 27 of FIG. 4A) is positioned insidemicrograft 100 (shown in cross section) and is connected to tube 129(similar to tube 29 of FIG. 4A but without the tab 29 a) in a similarmanner as core 27 and tube 29. Tube 129 has a window (opening) or cutout(slot) 206 forming a receiving portion therein configured to accommodateinsertion (and releasable engagement) of locking ball 198 from the top(as viewed in the orientation of FIG. 21A). Proximal of window 206 ontube 129 is a marker band 22′ similar to marker band 22′ of theembodiment of FIG. 4C, except having a lengthwise slot 210. The markerband 22′ can be attached to tube 129 via welding, soldering, adhesive,or other methods. Marker band slot 210 is sized and positioned such thatthe wire portion of ball lock wire 196 sits inside slot 210 when locksystem is engaged with micrograft 100. Tube 129 may be laser cut fromany metal tubing such as stainless steel or other alloys, likeplatinum/iridium or platinum/tungsten.

To couple the micrograft 100 to the locking system mounted on a pushmember 189, delivery wire 182 is advanced past the distal end 194 ofcoil 192 and micrograft 100 is then slid over the delivery wire 182until tube 129 comes in contact with locking ball 198. Tube 129 is thenpushed further proximally (pushing locking ball 198 out of the way),pushing against distal end 194 of coil 192 causing the coil 192 tocompress. When coil 192 is sufficiently compressed, lock ball 198 slipsinto and engages window (opening) 206 of tube 129. While keeping thecoil 192 in compression and locking ball 198 seated in window 206,introducer sheath or catheter 208 is advanced over the assembly toprevent locking ball 198 from deflecting out of window 206 and tocomplete the lock. The lock is engaged as long as tube 129 and lock ball198 remain inside the sheath 208. Once outside the sheath 208, thecompressed coil 192 returns to it normal non-compressed configuration,pushing tube 129 distally with a distally directed force, causing lockball 198 to slip out and disengage micrograft 100 and pushing themicrograft 100 to the target site. (Note the delivery wire 182 isretracted from the micrograft 100). In the embodiments where the lockingsystem is placed on a push wire assembly such as push wire 188 of FIG.20A, the coupling steps for locking a micrograft to the lock would bethe same with the exception of inserting the delivery wire 182, which isabsent in the push wire design. The micrograft would be released in thesame fashion as described above as the ball is freed from the confinesof the sheath (and hood if provided) to enable it to move laterally todisengage from the tube 129. Also note that the locking hook 204 of theembodiment of FIG. 20B would be assembled/coupled to the micrograft inthe same manner as described above (depending if attached to a pushermember 189 as in FIG. 20B or attached to a pusher wire such as pusherwire 188 of FIG. 20A). The micrograft would be released from the hook204 in the same manner as the locking ball 198 is released from thesheath (and hood if provided) to enable it to disengage from the tube129.

The embodiment of FIGS. 22A-22C is similar to the embodiment of FIGS.21A and 21B, however, in addition to the slot 210 of marker band 22′,tube 129′ has a matching slot 212 as shown in the cross-sectional viewof FIG. 22A which runs lengthwise from window (opening) 206 to proximalend of tube 129′. Otherwise, tube 129′ is similar to tube 129. Also,FIGS. 22A-22C differ, as noted above, as they depict a version oflocking system 190 which has laser cut locking wire 214 and ball 216formed from a single laser cut tube 218. Inside and outside dimensionsof the laser cut tube 218 can overlap with those of tube 129. That is,the dimension of tube 218 at wire region 214 could be greater or lessthan or equal to the dimension of tube 129′. FIG. 22B provides anexample where the dimension of wire portion 214 is less than thedimension of tube 129. Utilizing tubes of the same diameters preventslaser cut lock tube 218 and tube 129′ from stacking and achieves minimalradial profile while the lock wire and ball sit inside the slot andwindow of tube 29. In FIG. 21A, the locking wire 192 extends external oftube 129 within slot 210 of marker band 22′, positioned between tube 129and the inner wall of the sheath 208 while in FIG. 22A, the locking wire214 is internal of the marking band 22′ and extends in slot 212 of tube129′. When aligned, slot 210 and slot 212 form a V-shapedcross-sectional cut through the walls of marker band 22′ and tube 129,which gives the locking ball a tendency to slide radially toward thewider section of the slot while in tension (when the coil iscompressed). The lock ball 216 diameter is large enough to prevent theball from pulling out of the tube/marker band V-slot when the assemblyis inside an introducer sheath or delivery catheter. The ball 216 willeasily slip out and disengage from tube 129′ when the system is advancedout of sheath 208, with the compression coil 192 applying a pushingforce on the released micrograft 100. This version of the locking systemmay be used with or without delivery wire 182. This slotted tube 129′design can be used with any of the previously described locking ball orhook designs.

FIGS. 23A and 23B show an alternative version of the locking systemattached to a pusher wire 188. This version of the locking system has alock wire (elongated member) 219 with a bend or elbow 220, bending at anangle to the longitudinal axis of the lock wire 219. For this lock toengage, ball 221 is inserted into tube 129 of micrograft 100 so thatelbow 220 sits partially or completely inside the lumen of tube 129 withball 221 positioned inside window 206 while coil 192 is compressed bythe coupling of the micrograft (coupled in a similar manner as describedabove). When the introducer sheath 208 is advanced over the engagedlocking system, the assembly is constrained so that the curved lock wire219 is hooked on tube 129 and micrograft 100 is coupled for delivery.Advancing the system out of the sheath 208 causes the compressed coil topush micrograft 100 off the lock wire and detach (release) from the lockwire 219.

Note that although the engaging members are shown in the form of a balllock or hook in the delivery systems described herein, other engagingstructures are also contemplated. It should also be understood that thelocking assembly described herein can be utilized with or without adelivery wire, and a hood can be provided in any of the systems.

FIG. 24 illustrates another embodiment of an intra-aneurysmal micrograftdelivery system generally referred to by reference number 222. Deliverysystem 222 is designed to deliver a flow diverter 224 in combinationwith a micrograft 100 on a single delivery wire 226 using locking system190 by way of example for micrograft attachment. One or more micrograftsmay be loaded on the delivery wire (using previously described methods)in tandem with a stent or flow diverter for more efficient delivery.Also, instead of a flow diverter a stent can be loaded within sheath208. Note the flow diverter (or stent) is positioned proximal of themicrograft for delivery after delivery of the micrograft. Although lockball arrangement of FIG. 24 is shown, other locking systems describedherein can also be utilized.

In use, the system 222 is introduced and tracked through a microcatheterwhich has been positioned with its distal tip in an aneurysm. Themicrograft 100 would be deployed into the aneurysm first, the n themicrocatheter tip would be pulled back into the parent vessel andpositioned for delivery of the flow diverter (or stent). The flowdiverter would then be delivered. Once flow diverter 224 is delivered,the microcatheter would be removed. For this design, locking system 190and the delivery wire 226, can have coils distal of the flow diverter,and the coils and/or the flow diverter may be radiopaque to helpidentify wire position during interventional procedures.

FIGS. 12A through 12C show directed delivery of micrograft 10 of FIG. 1inside an intracranial aneurysm. Other micrografts described herein canbe delivered in a similar manner. Unlike micrograft delivery describedin FIGS. 10 and 11A-11F above, in the embodiment of FIGS. 12A and 12B,the shaped delivery wire 62′ remains in the aneurysm so that themicrograft deployment can be directed to a targeted location (neck)within the aneurysm sac. FIG. 12A illustrates a distal tip 66′ ofdelivery wire 62′ that has been shape set in a “J” and deployed so thatthe “J” points at the stent or flow diverter 154 covering the neck ofthe aneurysm. As the pusher catheter 58 is advanced distally, themicrograft 10 will deploy and follow along the delivery wire 62′ in adirection denoted by arrow 162 towards the stent or flow diverter 154.

FIG. 12B illustrates a delivery wire 62′ that has been shape set with a“J” and advanced into the dome of the aneurysm. As the micrograft 10 isadvanced it will follow the curvature of the wire 62′ in a directiondenoted by arrow 164.

FIG. 12C illustrates that the microcatheter 146 can be used to directmicrograft deployment within the aneurysm. The delivery wire has beenpulled back into microcatheter 146 which is seated in the neck of theaneurysm 158. As the micrograft 10 is advanced it will follow thedirection denoted by arrow 166. The tip of the microcatheter 146 can becurved to direct the micrograft 10. When the micrograft 10 encountersbarriers, such as the aneurysm wall, it will easily change direction asdepicted.

FIG. 13 illustrates the deployment of flow directed micrografts 168using intra-aneurysmal micrograft delivery system 54 with delivery wire62′ having a “J” form at its tip and extending from microcatheter 146.Micrografts 168 can have the same structure as other micrograftsdescribed herein. Flow directed micrograft 168 can be any length, butshorter lengths such as about 2 mm to about 5 mm are utilized in thisembodiment so as to move with blood flow. Since the flow directedmicrografts 168 tend to be shorter than micrografts configured to fillthe aneurysm, many more flow directed micrografts can be loaded onto thedelivery wire and consecutively deployed, as illustrated in FIG. 13 .Micrograft 168 has been shape set into a “C” shape, however, othershapes are also contemplated as discussed above.

As each micrograft 168 is advanced distally off the delivery wire 62′,it will be caught up in blood flow exiting the neck of the aneurysm. Dueto the stent or flow diverter 154 blocking the neck 158, micrograft 168will be restricted from exiting into parent vessel 170. When asufficient amount of micrografts 168 are introduced into the aneurysm,the micrografts will pile up and clog or create a localized graft at thestent/flow diverter and neck interface. Over time, thrombus will formabove the clog to aid in closing off the aneurysm. The smaller, shortermicrografts are intended to provide a more complete obstruction or fillvoids at the aneurysm neck.

FIG. 14 illustrates microcatheter 146 positioned inside the parentvessel 170. This embodiment differs from the previous embodiments inthat instead of extending in the space between the stent 154 and parentvessel 170, the microcatheter 146 extends through the struts or pores ofstent or flow diverter 154. In all other respects, the system is thesame as that of the aforedescribed systems. Note micrograft 10 is shownexiting the microcatheter 146 into the aneurysm. Longer length orshorter length micrografts can be delivered.

As discussed earlier, the delivery wire 62 can be a guidewire.Therefore, if desired, the micrograft delivery system with guidewire canbe loaded into the microcatheter prior to catheter placement. The entireassembly, microcatheter and micrograft delivery system, can then betracked to the aneurysm site using the delivery system's guidewire asthe primary tracking wire. Alternately, the guidewire and microcathetercan be tracked to the aneurysm site and rapid exchange catheter, e.g.,pusher catheter 80 of FIG. 6 , can be advanced subsequently.

FIG. 15 illustrates the distal end of intra-aneurysmal micrograftdelivery system 86 of FIG. 7 deploying micrograft 90. Micrograft 90 hasbeen released from arms 94, 98 and has assumed a pre-biased (pre-set)shape. As noted above, the micrografts can be pre-set to a variety ofconfigurations and the shapes illustrated in the drawings are providedby way of example. If desired, the micrograft 90 can be retrieved bycapturing a portion of the structure between arms 94, 98, and advancingthe microcatheter 146 over the arms to compress the arms. Alternately,the delivery arms 94, 98 can be used to compress or move the micrograftaround the aneurysm to aid in packing.

FIG. 18A provides a flow chart for one method of placing a micrograft ofthe present invention. This method utilizes the delivery system of FIGS.5A and 5C. The steps include:

-   -   1) Insert micrograft(s) over distal end of delivery wire 62        until micrograft rests on stopper or wire taper 70.    -   2) Insert delivery wire 62 into pusher catheter 58.    -   3) Insert delivery system into RHV 78 of microcatheter.    -   4) Track delivery system until wire tip 66 reaches aneurysm.    -   5) Pull back wire 66 and align with distal marker band of        micrograft in aneurysm.    -   6) Fill micrograft with blood by retracting wire tip 66 into the        micrograft.    -   7) Deploy micrograft by advancing pusher 58. Retract device if        proximal end still in microcatheter.    -   8) Remove delivery system from microcatheter.    -   9) If needed, repeat steps to deploy additional micrografts.

FIG. 18B provides a flow chart for another method of placing amicrograft of the present invention. This method utilizes the samedelivery system of FIGS. 5E-5H. The steps include:

-   -   1) Remove device from packaging and prepare per Instructions for        Use (IFU).    -   2) Insert delivery system with micrograft into microcatheter        RHV.    -   3) If present, remove introducer sheath once micrograft is        inside microcatheter.    -   4) Track delivery system until wire tip 184 and distal end of        micrograft reach the treatment site.    -   5) Fill micrograft with blood by incrementally retracting wire        tip 184 just distal of the micrograft lock (tab 29 a).    -   6) Deploy micrograft by advancing delivery system (pusher 186        and wire 182). Pull delivery system to retract micrograft if        necessary.    -   7) Once out of microcatheter, detach micrograft by retracting        wire 182 (or advancing pusher) until wire bulb 184 pulls through        micrograft lock (tab 29 a) and into the pusher 186.    -   8) Remove delivery system from microcatheter.    -   9) If needed, repeat steps to deploy additional micrografts.

Note the delivery systems and occluding devices (micrografts) disclosedherein have been described for use for treating intracranial aneurysms.It should be appreciated that the delivery systems and occluding devices(micrografts) can also be utilized for treating aneurysms in otherregions of the body or for treating other vasculature or for treatingnon-vascular diseases.

Note the delivery systems disclosed herein can be utilized to deliverthe various micrografts disclosed herein and specific micrograftsdiscussed in conjunction with specific delivery systems are provided byway of example.

The above delivery systems and concepts are preferred ways to deliverthe intra-aneurysmal micrograft. The micrograft however mayalternatively be constructed to mate with other microcoil deliverysystems that provide a timed and controlled release, e.g., electrolyticdetachment as described in U.S. Pat. No. 5,354,295 and its parent, U.S.Pat. No. 5,122,136, both to Guglielmi et al., interlocking ball and keyway as described in U.S. Pat. No. 5,261,916 to Engelson, and pusher withmating ball configuration as described in U.S. Pat. No. 5,304,195 toTwyford et al.

In some applications, other vaso-occlusive devices such as platinummicrocoils may be used in combination with the micrografts of thepresent invention to occlude the aneurysm.

The delivery systems disclosed herein are for uses for deliveringdevices for treating intracranial aneurysms, however it is alsocontemplated that the delivery systems can be used to deliver devicesthrough and in other body lumens in a patient.

While the above description contains many specifics, those specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision many other possible variations that arewithin the scope and spirit of the disclosure as defined by the claimsappended hereto.

1. A vascular implant configured for occluding a vasculature of apatient, the vascular implant comprising: A biocompatible polymericstructure formed of a plurality of filaments and having a proximal endand a distal end, the filaments spaced to maintain surface porosity, thepolymeric structure forming a tubular body having a first longitudinallyextending opening; and A radiopaque coil having a proximal end and adistal end, the radiopaque coil positioned within the longitudinallyextending opening of the polymeric structure, wherein the polymericstructure and radiopaque coil are attached forming a joint at the distalend of the radiopaque coil along a length extending for at least 0.002inches and not exceeding a length of about 0.050 inches, the polymericstructure covering the distal end of the radiopaque coil.
 2. The implantof claim 1, wherein the joint is formed where the polymeric structurecovers at least two coil windings of the radiopaque coil.
 3. The implantof claim 2, wherein the two coil windings are distalmost windings of theradiopaque coil.
 4. The implant of claim 2, wherein the two coilwindings are spaced proximally of a distalmost end of the radiopaquecoil.
 5. The implant of claim 1, wherein the joint of the polymericstructure and radiopaque coil is formed by application of energy to bondthe polymeric structure and radiopaque coil.
 6. The implant of claim 1,wherein the joint of the polymeric structure and radiopaque coil isformed by an adhesive to bond the polymeric structure and radiopaquecoil.
 7. The implant of claim 1, wherein the polymeric structure andradiopaque coil are attached forming a joint along a length of about0.004 inches to about 0.020 inches.
 8. The implant of claim 1, furthercomprising a metal tube attached to a proximal end of the radiopaquecoil, wherein the polymeric structure and metal tube are attached toform a proximal joint along a length extending for at least 0.002 inchesand not exceeding a length of about 0.050 inches.
 9. The implant ofclaim 8, wherein the proximal joint of the polymeric structure and metaltube is formed by one of application of energy or an adhesive to bondthe polymeric structure and metal tube.
 10. The implant of claim 8,wherein the polymeric structure is further attached to the radiopaquecoil to form the proximal joint, the proximal joint formed by one ofapplication of energy or an adhesive to bond the polymeric structure,metal tube and radiopaque coil.
 11. (canceled)
 12. The implant of claim1, wherein the polymeric structure has a series of peaks and valleysalong a surface of a wall to increase flexibility, the peaks and valleysformed by crimping of the polymeric structure.
 13. The implant of claim1, wherein the polymeric structure and radiopaque coil are attached sothat the joint extends continuously along a length of the joint.
 14. Avascular implant configured for occluding a vasculature of a patient,the vascular implant comprising: a biocompatible polymeric structureformed of a plurality of filaments and having a proximal end and adistal end, the filaments spaced to maintain surface porosity, thepolymeric structure forming a tubular body having a first longitudinallyextending opening; and an inner element composed of a radiopaque coilhaving a proximal end and a distal end, the radiopaque coil positionedwithin the longitudinally extending opening of the polymeric structure,wherein the polymeric structure and radiopaque coil are attached to forma joint at the distal end of the radiopaque coil along a length whereinthe joint covers at least two distalmost coil windings of the radiopaquecoil.
 15. The implant of claim 14, wherein the joint of the polymericstructure and radiopaque coil is formed by application of energy to bondthe polymeric structure and radiopaque coil or by an adhesive to bondthe polymeric structure and radiopaque coil.
 16. (canceled)
 17. Theimplant of claim 14, wherein the at least two coil windings of theradiopaque coil are spaced from a distalmost end of the radiopaque coil.18. A vascular implant configured for occluding a vasculature of apatient, the vascular implant comprising: a biocompatible polymericstructure formed of a plurality of filaments and having a proximal endand a distal end, the filaments spaced to maintain surface porosity, thepolymeric structure forming a tubular body having a first longitudinallyextending opening; and an inner element composed of a radiopaque coilhaving a proximal end and a distal end, the radiopaque coil positionedwithin the longitudinally extending opening of the polymeric structure,wherein the polymeric structure and radiopaque coil are attached at aplurality of discrete spaced apart non-continuous regions at a distalportion of the radiopaque coil, wherein a distance from a proximalmostdiscrete region to a distalmost discrete region is between about 0.002inches and about 0.050 inches.
 19. The implant of claim 18, wherein thefilaments form a plurality of yarns, the plurality of yarns havingspaces therebetween for blood inflow between the yarns.
 20. The implantof claim 19, wherein the polymeric structure has a series of peaks andvalleys along a surface of a wall to increase flexibility, the peaks andvalleys formed by crimping of the polymeric structure.